Choosing a 35mm Film Camera (written in 2003)
FOREWORD
The following article was written a long time ago during the age of the SLR (no "D"). At one point, we used something called "film" to do our astrophotography. I include the article here, in October 2017, for a couple of reasons:
The following article was written a long time ago during the age of the SLR (no "D"). At one point, we used something called "film" to do our astrophotography. I include the article here, in October 2017, for a couple of reasons:
- I believe it's important to know something about our hobby's origins in order to be able to appreciate what we can do today.
- You get an idea of where I was in the hobby 15 years ago.
- For the sake of posterity...there is a lot of history written about here...about the major camera companies, their product histories, and how their cameras faired against the competition.
- Because there are principles here that underlie all of astro imaging - so you can gain key insights when you realize that as much as things have changed, they've also stayed mostly the same.
INTRODUCTION
Since I assume that you are interested in astrophotography for the long-haul, I've got some concrete ideas about the way you should proceed in finding a 35mm SLR suitable for astrophotography. You see, if you are in it as a long-term hobby, then you should understand the demands of that camera system. It may be enough for you at first to take some decent photos of star fields and constellations, but you soon hope to shoot for more. You get narrower and narrower; longer and longer with your exposures. You begin to look for superior lens/scope systems, with long focal lengths, fast speeds, flat fields, no spherical aberrations/vignetting, and good color correction. You look for ways to be more critical with your focus in an attempt to achieve the tightest star images possible. You look for the best films available to astrophotography and even resort to stocking up tens of roles at a time and perhaps even purchasing a hypering rig. You keep Kodak and Fuji email addresses handy because you know that they are about to change you favorite emulsion for the worst and you need to let off some steam.
So first of all, you need to ask yourself if you are interested in purchasing a single camera that will best fit a life-time program of imaging. Or, perhaps you just want a camera that will get you started hoping to upgrade in the future. Well, I'm going to assume the former rather than the latter. Afterall, isn't this question about finding the best astro camera available? Since I believe it is, I'll try to answer by giving qualities of good cameras, including some specific examples of cameras that I believe may be the best. I'll also demonstrate what you might expect from such cameras and lenses with examples from actual images. With that framework, I'll trust you to determine if you want to spend the money for that camera or choose one that you can "live with."
FIRST THINGS FIRST
The common misconception is that you simply need a camera to connect to the back of a telescope. Sorry to disappoint you, but if that is where you plan to start you've got some headaches on the road ahead. Astrophotography should start at shorter focal lengths and go up from there as you gain experience and equipment. That means using the cameras existing lenses instead of your telescope, at least for a while. The reason for this is that as you go up in focal length, taking pictures becomes almost exponentially more difficult. You may be impressed with some of the pictures you see in my own galleries, but as of the writing of this article in June, 2003, you should note that not many of them are taken through the telescope at "prime focus." Everything you see in color is a piggyback shot (or shots) with existing camera lenses. I've taken tons of color images through the scope, but I don't feel that any of them are worthy of displaying. That's because I haven't perfected the techniques of shooting at such long focal lengths, and I still haven't worked the bugs out of my equipment. Both factors work against me in producing prime focus images. They will work against you as well.
Connecting that camera to a telescope before you know what you are doing (or what to expect) might make you throw that camera into the closet. Or back into the closet should you already have a decent astro camera.
If not hooking up to the telescope, then where do we start? Easy...we start with the lenses of the camera, preferrably the smallest one. We do this on a tripod, on an equatorial mount, or on top of an existing telescope riding piggyback. For this reason, you need a camera that can provide a good set of lenses as well. For me, that's the most important aspect. You can take decent photos with any camera, but great photos are made with great lenses (and great telescopes). It's all about the glass!
So it's really not a camera we are looking for...it is a camera system. With that knowledge we will explore what to look for in a good 35mm astrophotographic system.
ASPECTS OF THE CAMERA
This is what you wanted to know...what makes for the best 35mm camera for use in astrophotography? I'll tell you the most important aspects in order of importance; therefore, if you can't afford a certain camera that I mention you can compare these aspects with a camera you can afford.
It's all about the glass...
The best camera for you, regardless of all other aspects of the camera body itself, are the ones that give you the access to the best lenses. Generally speaking, Canon and Nikon are heads of the class here. Now that's not to say that good lenses cannot be found for other brandnames. Minolta, Pentax, and Olympus (among others) all have various lines of lenses that produce superior results, but Canon and Nikon have a greater consistency of great lenses in all existing lines. But it stands to reason that the best lenses for astrophotography have the same qualities as good photographic telescopes. Such lenses, regardless of manufacturer, will have some type of ED (extra-low dispersion) glass or even fluorite coatings.
Some third-party companies make nice lenses as well. Some lenses from Sigma and Tamron, and Tokina, among others, are produced with ED glasses and are made to fit a variety of mounts. But once again, such lenses are expensive. In general, "normal" third party lenses are to be avoided because they are often considered inferior to the "real thing."
Initially, you will not start out with these great lenses, unless of course you can afford them. So from that point of view you can actually start out with any lenses. But this is the thing to keep in mind for later. Will this camera allow for great glass should I need it? This will be the deciding factor among cameras that appear to be similar in both form and function.
But don't be disheartened. You may already have some lenses that will work acceptably. Lenses, as with telescopes, vary greatly in their performance. Some lenses, like my regular Nikon Nikkor 135mm f2.5 lens works acceptably well as I'll demonstrate later. Others, like my Nikon Nikkor-Q 200mm f4 lens, which costs more incidently, produces much worse images, as does my normal 50mm f/1.4 lens. Plus, stopping down the aperture of any lens, thus avoiding some of the aberrations inherent at the edge of lens, just might give you some surprising results.
Dump the electronics...
The electronic revolution in cameras took a big leap in the mid-70s with the proliferation of electronic through-the-lens (TTL) metering and electromechanical shutters. The three camera models that put together complete electrical systems of these types were the Pentax ME (1975), the Contax RTS (1975), and the Minolta XD-7 (1976). They were the first to utilize full aperture and shutter priority modes. In response to these systems, the other major makers stepped up their electronic features in a major way. Incidently, all of these cameras utilize a full-manual backup in bulb mode.
The second major revolution in the camera industry occurred with the utilization of auto-focus (AF) capabilities. The Pentax ME-F (1981) was the precursor of this design utilizing a focus-assist capability where an LED light indicated true focus on their current lenses. From there, Nikon incorporated complete motorized focusing in a version on their Nikon F3AF in 1985, with Canon jumping into the act with their Canon T-80 in the same year. New AF lenses were introduced for these models over this time, though they still maintained compatibility with older lenses. But it was Minolta who developed the first truly integrated AF system, that is, a camera body with a complete set of AF lenses and no backward lenses compatibility. This was the Minolta Maxxum 7000 introduced in 1985. At this point, Nikon countered with their F4 and Canon with their EOS system, both in 1988.
These two revolutions have important implications for the beginning astrophotographer.
Since I assume that you are interested in astrophotography for the long-haul, I've got some concrete ideas about the way you should proceed in finding a 35mm SLR suitable for astrophotography. You see, if you are in it as a long-term hobby, then you should understand the demands of that camera system. It may be enough for you at first to take some decent photos of star fields and constellations, but you soon hope to shoot for more. You get narrower and narrower; longer and longer with your exposures. You begin to look for superior lens/scope systems, with long focal lengths, fast speeds, flat fields, no spherical aberrations/vignetting, and good color correction. You look for ways to be more critical with your focus in an attempt to achieve the tightest star images possible. You look for the best films available to astrophotography and even resort to stocking up tens of roles at a time and perhaps even purchasing a hypering rig. You keep Kodak and Fuji email addresses handy because you know that they are about to change you favorite emulsion for the worst and you need to let off some steam.
So first of all, you need to ask yourself if you are interested in purchasing a single camera that will best fit a life-time program of imaging. Or, perhaps you just want a camera that will get you started hoping to upgrade in the future. Well, I'm going to assume the former rather than the latter. Afterall, isn't this question about finding the best astro camera available? Since I believe it is, I'll try to answer by giving qualities of good cameras, including some specific examples of cameras that I believe may be the best. I'll also demonstrate what you might expect from such cameras and lenses with examples from actual images. With that framework, I'll trust you to determine if you want to spend the money for that camera or choose one that you can "live with."
FIRST THINGS FIRST
The common misconception is that you simply need a camera to connect to the back of a telescope. Sorry to disappoint you, but if that is where you plan to start you've got some headaches on the road ahead. Astrophotography should start at shorter focal lengths and go up from there as you gain experience and equipment. That means using the cameras existing lenses instead of your telescope, at least for a while. The reason for this is that as you go up in focal length, taking pictures becomes almost exponentially more difficult. You may be impressed with some of the pictures you see in my own galleries, but as of the writing of this article in June, 2003, you should note that not many of them are taken through the telescope at "prime focus." Everything you see in color is a piggyback shot (or shots) with existing camera lenses. I've taken tons of color images through the scope, but I don't feel that any of them are worthy of displaying. That's because I haven't perfected the techniques of shooting at such long focal lengths, and I still haven't worked the bugs out of my equipment. Both factors work against me in producing prime focus images. They will work against you as well.
Connecting that camera to a telescope before you know what you are doing (or what to expect) might make you throw that camera into the closet. Or back into the closet should you already have a decent astro camera.
If not hooking up to the telescope, then where do we start? Easy...we start with the lenses of the camera, preferrably the smallest one. We do this on a tripod, on an equatorial mount, or on top of an existing telescope riding piggyback. For this reason, you need a camera that can provide a good set of lenses as well. For me, that's the most important aspect. You can take decent photos with any camera, but great photos are made with great lenses (and great telescopes). It's all about the glass!
So it's really not a camera we are looking for...it is a camera system. With that knowledge we will explore what to look for in a good 35mm astrophotographic system.
ASPECTS OF THE CAMERA
This is what you wanted to know...what makes for the best 35mm camera for use in astrophotography? I'll tell you the most important aspects in order of importance; therefore, if you can't afford a certain camera that I mention you can compare these aspects with a camera you can afford.
It's all about the glass...
The best camera for you, regardless of all other aspects of the camera body itself, are the ones that give you the access to the best lenses. Generally speaking, Canon and Nikon are heads of the class here. Now that's not to say that good lenses cannot be found for other brandnames. Minolta, Pentax, and Olympus (among others) all have various lines of lenses that produce superior results, but Canon and Nikon have a greater consistency of great lenses in all existing lines. But it stands to reason that the best lenses for astrophotography have the same qualities as good photographic telescopes. Such lenses, regardless of manufacturer, will have some type of ED (extra-low dispersion) glass or even fluorite coatings.
Some third-party companies make nice lenses as well. Some lenses from Sigma and Tamron, and Tokina, among others, are produced with ED glasses and are made to fit a variety of mounts. But once again, such lenses are expensive. In general, "normal" third party lenses are to be avoided because they are often considered inferior to the "real thing."
Initially, you will not start out with these great lenses, unless of course you can afford them. So from that point of view you can actually start out with any lenses. But this is the thing to keep in mind for later. Will this camera allow for great glass should I need it? This will be the deciding factor among cameras that appear to be similar in both form and function.
But don't be disheartened. You may already have some lenses that will work acceptably. Lenses, as with telescopes, vary greatly in their performance. Some lenses, like my regular Nikon Nikkor 135mm f2.5 lens works acceptably well as I'll demonstrate later. Others, like my Nikon Nikkor-Q 200mm f4 lens, which costs more incidently, produces much worse images, as does my normal 50mm f/1.4 lens. Plus, stopping down the aperture of any lens, thus avoiding some of the aberrations inherent at the edge of lens, just might give you some surprising results.
Dump the electronics...
The electronic revolution in cameras took a big leap in the mid-70s with the proliferation of electronic through-the-lens (TTL) metering and electromechanical shutters. The three camera models that put together complete electrical systems of these types were the Pentax ME (1975), the Contax RTS (1975), and the Minolta XD-7 (1976). They were the first to utilize full aperture and shutter priority modes. In response to these systems, the other major makers stepped up their electronic features in a major way. Incidently, all of these cameras utilize a full-manual backup in bulb mode.
The second major revolution in the camera industry occurred with the utilization of auto-focus (AF) capabilities. The Pentax ME-F (1981) was the precursor of this design utilizing a focus-assist capability where an LED light indicated true focus on their current lenses. From there, Nikon incorporated complete motorized focusing in a version on their Nikon F3AF in 1985, with Canon jumping into the act with their Canon T-80 in the same year. New AF lenses were introduced for these models over this time, though they still maintained compatibility with older lenses. But it was Minolta who developed the first truly integrated AF system, that is, a camera body with a complete set of AF lenses and no backward lenses compatibility. This was the Minolta Maxxum 7000 introduced in 1985. At this point, Nikon countered with their F4 and Canon with their EOS system, both in 1988.
These two revolutions have important implications for the beginning astrophotographer.
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First, you won't be needing a camera with an electromechanical shutter. Such advancements are more of a nuisance than a help in taking long-exposure astrophotos. For example, if your camera doesn't have the ability to open it's shutter in "bulb" or "B" mode without draining its batteries, then you're in trouble. Camera batteries can drain fast with the shutter open, especially in cold conditions. Trust me, you don't want to replace batteries on your first night out after having taken only five 10 minute exposures. Thus, you can rest assured that any camera manufactured prior to 1975-76 will have some type of manual shutter operation in bulb mode, though some will not have manual capabilities using other shutter speeds.
Secondly, what good is "Auto-Focus" if there is nothing bright enough to focus on? Therefore, these types of cameras can be eliminated completely unless they are backward compatible with older, manual focus lenses and they have retained a manual shutter in bulb mode. The Nikon F3AF, made in 1982, is a perfect example of such a camera. |
Important Aside: Some auto-focusing cameras can still work for astrophotography by using them in manual mode. But because we are attempting to find the perfect 35mm astrocamera, I choose to eliminate them from consideration. However, it should be noted that these cameras (and any camera we eliminate) can still be used with some level of effectiveness in taking pictures of the heavens. |
Therefore, you are looking for an older camera with both a manual (mechanical) shutter and manual lenses. That's a good thing because these types of cameras can be picked up for a song, used, of course. Alternatively, you could pick up a more recent electromechanical shuttered camera that allows for no power usage in the bulb setting, while functioning normally on other shutter speeds. You will be using settings other than bulb on occasion, like on the moon and sun, but those shots are short enough to prevent battery drain. So cameras like this can still be excellent for astrophotography.
Since we are searching for the perfect 35mm astrocamera, the first thing we should do is eliminate all "non-manual" shutter and "non-manual" focus cameras, and at the minimum, we should eliminate those that do not provide a completely manual setting in bulb mode. Therefore, to know what these cameras are, an awareness of the cameras produced by the major camera manufacturers is helpful. At the end of the article I will provide a timeline of cameras among each of these major makers with an emphasis on the point when their cameras became too "electronic."
So based on the prerequisite need for a manual focus camera, we've already narrowed down our search considerably.
Since we are searching for the perfect 35mm astrocamera, the first thing we should do is eliminate all "non-manual" shutter and "non-manual" focus cameras, and at the minimum, we should eliminate those that do not provide a completely manual setting in bulb mode. Therefore, to know what these cameras are, an awareness of the cameras produced by the major camera manufacturers is helpful. At the end of the article I will provide a timeline of cameras among each of these major makers with an emphasis on the point when their cameras became too "electronic."
So based on the prerequisite need for a manual focus camera, we've already narrowed down our search considerably.
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Interchangeable focusing screens...
This might be more important than a fully manual shutter, but I'll place it here. The first thing the beginner should understand is that the focusing screen found in 99% of all cameras will have a screen that's is not a bright as it could be. Most cameras are made for daylight, terrestial photography where focusing is more easily accomplished with a fresnel screen. These common screens normally have a split prism in the center, where focus is achieved by aligning objects on both halves. The rest of the screen is etched in such a way that light throughput is diminished considerably to soften the effect of daylight on the eye. It almost goes without saying that when using a camera in the dark, you don't need anything in the camera itself working against you. For this reason, a brighter focusing screen, one that passes more light to the eye, is necessary for visual focusing and object framing on the night sky. Therefore, any camera without the capability to change the focusing screen is NOT a good choice for astrophotography. Fortunately, many cameras have this capability. But this is more true of the professional series of cameras among the major camera makers than it is of the more consumer oriented lines. For example, the Olympus OMs, the Nikon Fs, the Canon F1, and the more expensive (at the time of their production) Pentaxs and Minoltas will more than likely have interchangeable focusing screens. Anything less might not. The otherwise great Pentax K1000, Nikon FM, and Minolta SRT-101 do not have an interchangeable focusing screen, nor do the Canon FTs, the Canon LTs, and the Nikkormat FTs. The implication of this is that the old manual 35mm camera you've kept in your closet for the last 30 years may NOT be the best choice for photography. |
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Installing a screen is usually a snap. Removable prism cameras allow you to simply drop the screen through the top, as shown at right on my Nikon F2. Such screens are framed nicely with a holder that fits specifically to each Nikon model. The screen does have to be pushed down firmly, especially when changing prisms; otherwise, proper focus can be a bit off because the idea of a focus screen is to be placed at exactly the same distance in the optical train as the film plane itself. Thus, WYSIWYG (what you see is what you get)! Focus screens in most other cameras, such as my Olympus OM-4, seen below, can be accessed through the front. Normally, a lever is depressed and the screen drops down.
Once you know the focusing screen can be changed, the next, often difficult step, is finding the proper focusing screen for your camera, preferrably one of the "matte" type or non-etched screens. Every camera maker produces a standard set of such screens for their cameras with such capabilities. Knowing which one to get is difficult since many of these screens are model specific. So often it takes some research to figure out which screen, if any, can be used for your camera.
This is often made easy by purchasing a third-party screen specifically for your camera. Beattie Intenscreens and the Brightscreen are popular alternatives and are made precisely for astrophotography; however, the number of camera bodies that these screen work with are limited. Plus, you'll pay a pretty penny for these screens as well. But these normally do outperform the best screens made by the major camera makers.
As for the screens made by the major manufacturers, some work tremendously well. For example, the Nikon F cameras had optional matte screens, known as the "C" and "D" screens that work very well with their respective models. I use a "C" screen with my Nikon F2, which works wonderfully; however, the F3 screens are brighter and are not compatible with the F2. With ingenuity, the great "D-red dot" screen for the F3 can fit into the F2 by removing the F3 screen from its frame and placing it into an F2 frame. Then, it just drops right in. With the Olympus OM series, the "1-8" and "1-11" screens seem to be the preferred choices among astrophotographers.
Outside of Nikon and Olympus, you'll have to do your research on the best screen for your own camera. However, with a bit of ingenuity you might find a way to make a different screen work well for you.
It should be noted that the use of an alternative focusing technique like knife-edge focusers, Hartmann masks, and Ronchi gratings can allow accurate focusing with cameras that do not have bright focusing screens. But even so, you will lose the ability to accurately frame the object that you wish to capture on film, something I consider imperative in the "perfect" 35mm astro camera.
The ability to blow your top...
I rank this higher than others do. For me, the perfect astro camera MUST have a removable or interchangeable prism. It means the difference between focusing through the camera or needing some other focusing aid, like a knife edge focuser, Ronchi screen, or Hartmann mask. It also means the ability to easily frame your object in the camera.
However, many experts will contend that critical focusing cannot be accomplished with a visual method. Of course, I disagree though I do think a 6x magnifying prism like the Nikon DW-2 for the Nikon F2 is a bit on the small side - cameras with bright focusing screens still need some magnification in order to see focused stars because they are, after all, only points, right? I still use the 6x magnification of the DW-2 prism with a certain level of success. But if this isn't sufficient, then a photographic loupe can often be shaved down to fit directly only the camera's focusing screen once the regular prism is removed. Such Loupes vary in magnification but many people find the ones in the 8x to 22x range very useful. I've even heard that some people set a telescope eyepiece directly on the focusing screen, having removed the prism, to give the magnification necessary to focus, but I cannot affirm the effectiveness of this. But when these items are set atop a bright focusing screen, critical focus literally becomes a snap.
Thus, without a removable prism, you lose the ability to achieve a critical and repeatable focus visually.
Some cameras without removable prisms can be accessorized with an eyepiece focusing aid, such as the popular Varimagni device for the Olympus cameras (which incidently fit some other camera makes as well). However, these are generally found to greatly hinder light throughput to the eye (small exit pupil) and are very much underpowered. Plus, they do not give access to the entire focus screen, as does a magnifying prism or loupe, so framing objects, if you can see the objects, becomes difficult. An alternative is a specialty focuser that allows a telescope eyepiece to be attached to the viewfinder of the camera. It works better than a Varimagni because the larger exit pupil gives a brighter image, but the image is still a bit dim and the magnification gain is still not enough to achieve critical focus.
The second advantage to a removable prism I mentioned earlier. When you have access to the focusing screen directly, framing the object becomes a piece of cake. No need to remove the camera and use an eyepiece to properly orient the object to be photographed. You will appreciate this, especially when you know you've already achieved the correct focus with the camera prior to orientation of the image. Refocusing all the time isn't all that fun.
My Nikon F2 camera and magnified prism, both shown at right, gives me eyepiece-quality views directly through the camera. No need to remove it to orient the image. In fact, it never ceases to amaze me when I see galaxies through the camera viewfinder. That's something that can't be done without a removable prism.
Unfortunately, the number of cameras with movable prisms comprises a short list and are considered the professional models of the product lines (i.e. expensive):
All Nikon F-series cameras
Canon F-1 or F-1(n)
Pentax LX
However, since the Nikon F4 and F5 are fully autofocus and electronically shuttered, these have already been excluded. So, in my mind, these remaining camera bodies are the only true choices for the "best" 35mm astro camera. Of course, the Nikon F3, the Canon and the Pentax are expensive for second-hand cameras. Which tends to make the Nikon F and Nikon F2 the best cameras on this criteria alone just from a price/performance aspect, though these models can be a bit expensive as well, especially if equipped with special prisms.
Mirror Lock-up, shmock up...
Overrated. That's my thought on this feature.
I've heard for years now, and read in every book on the topic, how important this thing called "Mirror Lock-up" is. I don't see it.
Mirror Lock-up is a feature of some 35mm cameras that prevents the shutter mirror from slapping up quickly at the first of the exposure. The idea is to lock the mirror in the "up" position manually prior to clicking the shutter. Therefore, any vibrations caused by the mirror-slap are negated and do not ruin your astrophoto at the first shutter press. When using long focal lengths on unsteady mounts, the shutter slap can cause everything to shake for up to, and sometimes exceeding, 10 seconds at the first of the exposure. It's like tapping the scope tripod at the first of the exposure. Vibrations need time to settle. If not, you'll have fat stars in your exposures.
Mirror Lock-up sounds good in theory, but not in practicality. There is not an exposure taken with my Nikon F2 (which has the mirror lock-up feature incidently) where I do not employ the "hat trick." This is the method of covering the front of the lens, or scope, with a dark object prior to releasing the shutter. Once the shutter is released, the object is removed and the light finds its way to the film. This method has a few advantages. First, it allows you to make sure all vibrations are cancelled out prior to removing the obstruction. This provides insurance not only against shutter "slap" but also against that sudden gust of wind or movement of a scope cable. Second, you can still apply the hat trick during the exposure in the event that a light pops up somewhere near you (handy for passing car lights). Third, it is a good practice for ending any exposure. Unlocking your shutter cable at the end of an exposure is often the source of some vibration. Ending with a hat trick is the best way to prevent this.
Those who do film photography, via eyepiece projection techniques, would definitely have a need for the mirror lock-up function. It becomes critical to time properly these short exposures of brighter objects. But with the shift toward digital photography for solar system objects, which can be accomplished much more effectively than with film, mirror lock-up is hardly necessary in a good astro camera.
ASPECTS OF THE LENS
Remember, it's all about the glass...
For this reason, if you are going to be picky about purchasing something, make sure it is the lens. Later I'll give you some specific camera models that are commonly used to produce great astrophotos, but for now allow me to describe what makes a good lens for astrophotography.
The aspects of a good camera lens for astrophotography is the same as those qualities you'd find in a good photographic telescope. Fast speeds, bright images with high contrast, true colors, flat fields to the edge of the film plane, and minimal vignetting (large image circle) are critical and can mean the difference between a good astrophoto and a great one.
Don't think that all lenses are suitable for astrophotography. There is not a more critical test for the quality of a lens than to take a shot of a field of stars. Lenses that are suitable for daylight shots are made to look bad when shooting a star field. Therefore, research into the quality of lenses for astrophotography becomes important. But one thing is for certain. A lenses that is great for astrophotography will also double as one of the best general-purpose lenses that you can find.
The essence of action and nature photography is that objects tend to move very quickly and you often need to take these shots from quite a distance away. Therefore, there is a tremendous market among photographers for lenses that are not only long in the focal lengths they need (to give the magnifications or field of view), but also "fast" enough to allow objects to be captured on film without a blurring of the image, especially in low light situations such as in nighttime sporting events or indoors. These same aspects of a lens required by action photographers are also the exact same requirements of astrophotographers. Photographing a night time sky on film requires the ability to put as much light on the film in the least amount of time. And it has to be able to accomplish this with a minimal amount of aberrations, vignetting, and false color. Like I said, a field of stars is a pretty mean test for any lens!
For a minute, let me describe the difference between photos taken with a "garden variety" lens and one that is considered to be better suited for astrophotography. Observe the following shots:
Once you know the focusing screen can be changed, the next, often difficult step, is finding the proper focusing screen for your camera, preferrably one of the "matte" type or non-etched screens. Every camera maker produces a standard set of such screens for their cameras with such capabilities. Knowing which one to get is difficult since many of these screens are model specific. So often it takes some research to figure out which screen, if any, can be used for your camera.
This is often made easy by purchasing a third-party screen specifically for your camera. Beattie Intenscreens and the Brightscreen are popular alternatives and are made precisely for astrophotography; however, the number of camera bodies that these screen work with are limited. Plus, you'll pay a pretty penny for these screens as well. But these normally do outperform the best screens made by the major camera makers.
As for the screens made by the major manufacturers, some work tremendously well. For example, the Nikon F cameras had optional matte screens, known as the "C" and "D" screens that work very well with their respective models. I use a "C" screen with my Nikon F2, which works wonderfully; however, the F3 screens are brighter and are not compatible with the F2. With ingenuity, the great "D-red dot" screen for the F3 can fit into the F2 by removing the F3 screen from its frame and placing it into an F2 frame. Then, it just drops right in. With the Olympus OM series, the "1-8" and "1-11" screens seem to be the preferred choices among astrophotographers.
Outside of Nikon and Olympus, you'll have to do your research on the best screen for your own camera. However, with a bit of ingenuity you might find a way to make a different screen work well for you.
It should be noted that the use of an alternative focusing technique like knife-edge focusers, Hartmann masks, and Ronchi gratings can allow accurate focusing with cameras that do not have bright focusing screens. But even so, you will lose the ability to accurately frame the object that you wish to capture on film, something I consider imperative in the "perfect" 35mm astro camera.
The ability to blow your top...
I rank this higher than others do. For me, the perfect astro camera MUST have a removable or interchangeable prism. It means the difference between focusing through the camera or needing some other focusing aid, like a knife edge focuser, Ronchi screen, or Hartmann mask. It also means the ability to easily frame your object in the camera.
However, many experts will contend that critical focusing cannot be accomplished with a visual method. Of course, I disagree though I do think a 6x magnifying prism like the Nikon DW-2 for the Nikon F2 is a bit on the small side - cameras with bright focusing screens still need some magnification in order to see focused stars because they are, after all, only points, right? I still use the 6x magnification of the DW-2 prism with a certain level of success. But if this isn't sufficient, then a photographic loupe can often be shaved down to fit directly only the camera's focusing screen once the regular prism is removed. Such Loupes vary in magnification but many people find the ones in the 8x to 22x range very useful. I've even heard that some people set a telescope eyepiece directly on the focusing screen, having removed the prism, to give the magnification necessary to focus, but I cannot affirm the effectiveness of this. But when these items are set atop a bright focusing screen, critical focus literally becomes a snap.
Thus, without a removable prism, you lose the ability to achieve a critical and repeatable focus visually.
Some cameras without removable prisms can be accessorized with an eyepiece focusing aid, such as the popular Varimagni device for the Olympus cameras (which incidently fit some other camera makes as well). However, these are generally found to greatly hinder light throughput to the eye (small exit pupil) and are very much underpowered. Plus, they do not give access to the entire focus screen, as does a magnifying prism or loupe, so framing objects, if you can see the objects, becomes difficult. An alternative is a specialty focuser that allows a telescope eyepiece to be attached to the viewfinder of the camera. It works better than a Varimagni because the larger exit pupil gives a brighter image, but the image is still a bit dim and the magnification gain is still not enough to achieve critical focus.
The second advantage to a removable prism I mentioned earlier. When you have access to the focusing screen directly, framing the object becomes a piece of cake. No need to remove the camera and use an eyepiece to properly orient the object to be photographed. You will appreciate this, especially when you know you've already achieved the correct focus with the camera prior to orientation of the image. Refocusing all the time isn't all that fun.
My Nikon F2 camera and magnified prism, both shown at right, gives me eyepiece-quality views directly through the camera. No need to remove it to orient the image. In fact, it never ceases to amaze me when I see galaxies through the camera viewfinder. That's something that can't be done without a removable prism.
Unfortunately, the number of cameras with movable prisms comprises a short list and are considered the professional models of the product lines (i.e. expensive):
All Nikon F-series cameras
Canon F-1 or F-1(n)
Pentax LX
However, since the Nikon F4 and F5 are fully autofocus and electronically shuttered, these have already been excluded. So, in my mind, these remaining camera bodies are the only true choices for the "best" 35mm astro camera. Of course, the Nikon F3, the Canon and the Pentax are expensive for second-hand cameras. Which tends to make the Nikon F and Nikon F2 the best cameras on this criteria alone just from a price/performance aspect, though these models can be a bit expensive as well, especially if equipped with special prisms.
Mirror Lock-up, shmock up...
Overrated. That's my thought on this feature.
I've heard for years now, and read in every book on the topic, how important this thing called "Mirror Lock-up" is. I don't see it.
Mirror Lock-up is a feature of some 35mm cameras that prevents the shutter mirror from slapping up quickly at the first of the exposure. The idea is to lock the mirror in the "up" position manually prior to clicking the shutter. Therefore, any vibrations caused by the mirror-slap are negated and do not ruin your astrophoto at the first shutter press. When using long focal lengths on unsteady mounts, the shutter slap can cause everything to shake for up to, and sometimes exceeding, 10 seconds at the first of the exposure. It's like tapping the scope tripod at the first of the exposure. Vibrations need time to settle. If not, you'll have fat stars in your exposures.
Mirror Lock-up sounds good in theory, but not in practicality. There is not an exposure taken with my Nikon F2 (which has the mirror lock-up feature incidently) where I do not employ the "hat trick." This is the method of covering the front of the lens, or scope, with a dark object prior to releasing the shutter. Once the shutter is released, the object is removed and the light finds its way to the film. This method has a few advantages. First, it allows you to make sure all vibrations are cancelled out prior to removing the obstruction. This provides insurance not only against shutter "slap" but also against that sudden gust of wind or movement of a scope cable. Second, you can still apply the hat trick during the exposure in the event that a light pops up somewhere near you (handy for passing car lights). Third, it is a good practice for ending any exposure. Unlocking your shutter cable at the end of an exposure is often the source of some vibration. Ending with a hat trick is the best way to prevent this.
Those who do film photography, via eyepiece projection techniques, would definitely have a need for the mirror lock-up function. It becomes critical to time properly these short exposures of brighter objects. But with the shift toward digital photography for solar system objects, which can be accomplished much more effectively than with film, mirror lock-up is hardly necessary in a good astro camera.
ASPECTS OF THE LENS
Remember, it's all about the glass...
For this reason, if you are going to be picky about purchasing something, make sure it is the lens. Later I'll give you some specific camera models that are commonly used to produce great astrophotos, but for now allow me to describe what makes a good lens for astrophotography.
The aspects of a good camera lens for astrophotography is the same as those qualities you'd find in a good photographic telescope. Fast speeds, bright images with high contrast, true colors, flat fields to the edge of the film plane, and minimal vignetting (large image circle) are critical and can mean the difference between a good astrophoto and a great one.
Don't think that all lenses are suitable for astrophotography. There is not a more critical test for the quality of a lens than to take a shot of a field of stars. Lenses that are suitable for daylight shots are made to look bad when shooting a star field. Therefore, research into the quality of lenses for astrophotography becomes important. But one thing is for certain. A lenses that is great for astrophotography will also double as one of the best general-purpose lenses that you can find.
The essence of action and nature photography is that objects tend to move very quickly and you often need to take these shots from quite a distance away. Therefore, there is a tremendous market among photographers for lenses that are not only long in the focal lengths they need (to give the magnifications or field of view), but also "fast" enough to allow objects to be captured on film without a blurring of the image, especially in low light situations such as in nighttime sporting events or indoors. These same aspects of a lens required by action photographers are also the exact same requirements of astrophotographers. Photographing a night time sky on film requires the ability to put as much light on the film in the least amount of time. And it has to be able to accomplish this with a minimal amount of aberrations, vignetting, and false color. Like I said, a field of stars is a pretty mean test for any lens!
For a minute, let me describe the difference between photos taken with a "garden variety" lens and one that is considered to be better suited for astrophotography. Observe the following shots:
Lagoon Nebula Region 135mm @ f4 Single 15 minute exposure Nikon 135mm f2.5 lens |
M24 420mm@ f4 Single 10 minute exposure Nikon 300mm ED f2.8 lens with 1.4x teleconverter |
The picture on the left, taken at the Texas Star Party in 2002, looks acceptable to most casual observers. An excellent region of the sky full of terrific objects, I decided to piggyback my camera atop my LX200 to capture this field. I used a 135mm, normal telephoto lens (yet one of high quality). But the shot is filled with problems, and the problems get worse toward the edge of the field. See for yourself (at right) in this expanded view of the upper left corner region, which includes the M25 open cluster.
Ignoring the grain and noise in this unprocessed image, two aspects of the enlarged image immediately demonstrate the problems inherent in the lens.
First, the star images are not round. This demonstrates that the lens does not provide a good, flat field. Due to the natural curvature of the lens elements, stars along the edges are decidedly elongated (though still better than many lens). Secondly, note the blue halos around some of the brighter stars. This is the "false" color that can arise from a lens that is not well corrected for color, akin to any lens or telescope that is "achromatic" in design. Even though it is a pleasant shot, the false color and spherical aberrations are still quite noticible.
What is important to note is that I took this shot stopped down from a possible f2.5 to f4. The property of any optical system is that spherical aberrations and false colors can be diminished greatly by shooting at slower f-stops on the lens, a good practice for any lens faster than f4. This by-passes the worst parts of the lens; around the edges. Therefore, what you are seeing in this enlargement is not as bad as it could have been had I taken the shot with the lens "wide open."
In the same way, take a look at the picture of M24 on the right of the Lagoon shot (below left). This photo was taken at the Texas Star Party in 2003 with a rather nice, and expensive, Nikon 300mm f2.8 ED lens (using a teleconverter) taken piggyback atop the LX200. Do you see any spherical aberrations or false color? Take a look at the expanded view of the upper left corner of the image near M17, the Swan Nebula.
Ignoring the grain and noise in this unprocessed image, two aspects of the enlarged image immediately demonstrate the problems inherent in the lens.
First, the star images are not round. This demonstrates that the lens does not provide a good, flat field. Due to the natural curvature of the lens elements, stars along the edges are decidedly elongated (though still better than many lens). Secondly, note the blue halos around some of the brighter stars. This is the "false" color that can arise from a lens that is not well corrected for color, akin to any lens or telescope that is "achromatic" in design. Even though it is a pleasant shot, the false color and spherical aberrations are still quite noticible.
What is important to note is that I took this shot stopped down from a possible f2.5 to f4. The property of any optical system is that spherical aberrations and false colors can be diminished greatly by shooting at slower f-stops on the lens, a good practice for any lens faster than f4. This by-passes the worst parts of the lens; around the edges. Therefore, what you are seeing in this enlargement is not as bad as it could have been had I taken the shot with the lens "wide open."
In the same way, take a look at the picture of M24 on the right of the Lagoon shot (below left). This photo was taken at the Texas Star Party in 2003 with a rather nice, and expensive, Nikon 300mm f2.8 ED lens (using a teleconverter) taken piggyback atop the LX200. Do you see any spherical aberrations or false color? Take a look at the expanded view of the upper left corner of the image near M17, the Swan Nebula.
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Shot with the lens fully open, with a teleconverter, the difference in the quality should be obvious.
First of all, the stars are only slighty elongated, something which can be expected with almost all other camera lenses not made with special glass. Such sharpness is only exceeded by top quality apochromatic (apo) refractors and astrographs. Considering the lens was used at its fastest setting, the shape of the stars are rather pleasing. Secondly, do you see false color? No. White stars are decidedly white. In other words, this super Nikon ED lens, as shown at right, made with extra-low dispersion glass like many apo and near-apo refractors, is well corrected for color. This despite the fact that the lense was taken wide open (again, not something widely practiced because of limitations of most lenses), and despite the fact that I used a teleconverter, which normally increases both aberrations and false color in an image. |
This speaks to a couple of great points regarding this set-up. First, it performs very similarly to the best apochromatic refractors of a similar focal length and aperture, and it does so at much faster speeds. Therefore, purchasing a good lens will certainly provide better shots than shooting at the prime focus of a short-tube, achromatic (achro) refractor. And secondly, the Nikon teleconverter is one of the best ever made. It is perfectly matched for this lens.
What you do not see in the above comparison is a significant amount of vignetting in both images. The M24 shot was somewhat processed, but there was no need to correct for vignetting. There is a slight amount of vignetting noticable in the above thumbnail (corrected for in the linked, final image). But this amount of vignetting was only slight, even insignificant. Thus, both lenses are good performers here, especially the 300mm since a teleconverter has the tendency to also increase vignetting.
But compare these images with a lens (and image) I am not very proud of (see below).
What you do not see in the above comparison is a significant amount of vignetting in both images. The M24 shot was somewhat processed, but there was no need to correct for vignetting. There is a slight amount of vignetting noticable in the above thumbnail (corrected for in the linked, final image). But this amount of vignetting was only slight, even insignificant. Thus, both lenses are good performers here, especially the 300mm since a teleconverter has the tendency to also increase vignetting.
But compare these images with a lens (and image) I am not very proud of (see below).
This is an unprocessed shot of the constellation Orion taken with my Nikon 50mm f1.4 lens. Not only do you see very fat, astigmatic stars, even close to the center of the image, but the vignetting is so significant that it rendered the shot un-processable. This combination of spherical aberrations, vignetting and false color (not noticable without enlarging) made this shot unsalvageable. Incidently, the photograph was a 10 minute exposure (a bit too close to the horizon) taken with the lens wide open at f1.4. Needless to say, if I shoot any more shots with this lense I will stop it down significantly, at least three stops to f4. That should reduce both the astigmatism and vignetting. How much, I do not know.
Using the above examples, it is my hope that you now understand the importance in choosing good lenses for your 35mm camera. It's also why you shouldn't choose a camera body without giving some consideration to the lenses available for it. Any lens can be made to work using certain techniques, like stopping down the aperture, or fixing problems in processing, but the idea behind a good lens is to give you the possibility of taking GREAT shots. As a beginner, you might be satisfied with the above Orion shot since your techniques will take time to refine anyway. But this shot, made by that 50mm lenses, is unfortunately typical of the results you can expect from most lens. Once again, it may shoot pretty shots during the day, but there is no more critical test of a lens' capabilities than with long exposures of the night sky.
When judging a lens by its aberrations, keep in mind that the shorter the focal length of the lens, the less important these issues become. Even though it is difficult to make a short focal length lens (sub-50mm) without aberrations when used under f4 or so, the fact that the stars become so small in such lenses tends to equal things out a bit. Therefore, most lens in these focal lengths work very well, unless of course it exhibits astigmatism, such as with the above example. As you go up in focal length, a more critical eye is required to find suitable lenses.
One final thought on lenses. Many people have zoom lenses that they would like to use for their astrophotos. Use them! But do so with an understanding of the limitations of the lens. Most zoom lenses are quite slower than their fixed, telephoto counterparts. They also contain more aberrations, more false color, and significantly more vignetting, especially at faster speeds and shorter focal lengths. Also, some zoom lenses tend to slide really easily, something you don't want to happen during a long film exposure pointed at the zenith! Therefore, if you do purchase a zoom lens, make sure it has some zoom locking mechanism to hold the slider in place.
You can certainly take some satisfying photos of the night sky with zoom lenses, just be sure you understand that you will be limited by the quality of that lens, not necessarily your techniques. This happens to be true of any lens.
ACCESSORIZING YOUR SYSTEM
Since you should be searching for a camera SYSTEM, let me make note of some of the things that you might need:
There are several (ten) guidelines for purchasing a camera system that should be heeded:
1.) Don't be afraid to purchase a camera with a broken light meter. The prices of these instruments will be very inexpensive because they are undesirable to general photographers. Likewise, any camera with the capability of removable prisms often can be purchased without a prism of any kind. This makes for a steal on the used market. The prisms often account for more than the price of camera body itself. If you are planning to add a magnifying prism or modified loupe anyway, you can save yourself some bucks.
2.) Purchase your camera equipment on eBay. Astromart is a popular place for used astronomy equipment, but the cameras, lenses, and focusing screens are generally over priced. Prices reflect a limited supply on Astromart. But the truth is that none of this equipment is scarce. Do a search on eBay for an Olympus OM-1 and you'll get around 100 hits. Prices here better reflect the demand of the camera. One on Astromart will go for $100 to $150 because its considered an "astrocamera." On eBay, it's just a used camera that nobody wants for more than $80. Likewise, the right focusing screen on Astromart will cost a pretty penny. But on eBay, the same focusing screen is just some screen that nobody uses.
There are exceptions to this rule. For example, the Nikon DW-2 6x magnifying prism for the Nikon F2 camera is considered a rare product. For this reason, these items are priced over $200 because that market has truly measured the limited supply. But on Astromart, they pop up all the time, and sometimes for a really good cost, which says a couple of things. First, a large portion of these prisms are already in the astronomy community. The rest are found among collectors of vintage cameras. Second, astrophotographers don't understand that the DW-2 is a collector's item. If they did, they'd sell it on eBay and make $50 more for it.
3.) Don't be too picky about the cosmetic condition of this used and vintage equipment. Most all cameras and lenses of this age will have a certain amount of normal wear. The wear drives down the price because vintage collectors are looking for mint or near-mint cameras.
For example, the seals that keep stray light out, located along the rear door and around the focus screen, might need to be replaced on most of these cameras anyway because the foam erodes after time, a condition known as "foam rot." Once purchased, a C.L.A. (Cleaning, Lubrication, and Adjustment) will need to be done by a local camera shop anyway, unless the camera is in satisfactory enough shape to work as is. Or, you can replace the seals yourself.
Likewise, minor brassing on the outside, especially near the strap hooks and across the base of the camera, should be expected. Scratches happen too and these scratches tend to make the camera less desirable to collectors, which is good for you, the beginning astrophotographer. You can't see the scratches and brassing in the dark anyway, right? The minor imperfections will simply drive the price down. Same thing for those cameras with broken light meters. Astrophotographers don't need them anyway.
4.) Do be aware of camera equipment with dents and major mechanical flaws. Dents are a sign that the equipment has been dropped. Not good for cameras, but especially not good for lenses. Chances are good that a dropped camera lens will exhibit optical aberrations beyond those naturally inherent in the design. Mechanically speaking, shutter speeds should be consistent throughout the entire range. The film advance lever should be smooth with all sprockets intact on the film take-up reel. The camera should be clean in the sense that it has not been exposed to dirty conditions. An excessive yellowing of the normally white indented markings on the camera could mean that the camera was in a smoker's environment or that it was exposed to moisture.
5.) Try to purchase camera components individually. Purchasing them in a package might net you a better deal, but some of the pieces are inevitably a "throw-in" item. What good are flashes, camera bags, lenses cases, filters, and hotshoes for astrophotography anyway? Don't purchase them unless they are specific to the item you want and you know you will need them.
6.) Judging the condition of camera equipment over the Internet is the most difficult part. ASK QUESTIONS! Get the assurance of the seller that the equipment will arrive in the same condition that he or she says it will be in. Get it guaranteed, if you can, or better yet, try before you buy if you are purchasing locally.
7.) Look for lenses with very few scratches on the optics, if at all, both inside and out. This is more important that the outer condition of the lenses itself. Some light scratches on the lenses might be acceptible as they probably will have a negligible effect on the end results. Just make sure the lens is priced to reflect these scratches. The same goes for stickers. I purchased my super Nikon 300mm ED lens complete with stickers, but the optics were pristine. The stickers gummed out the outside of the lens, but what did I care? Soon as I got the lens I "de-gummed" it anyway. If I sold it now I'd make a 70% profit on it!
No other condition should affect the price like good or bad glass. Many lenses will come with UV/daylight filters covering the front objective. This is a good thing. This indicates that the lens' front objective has been protected in some way by the filter.
If you are paying FULL price for a used lenses, make sure that the aperture blades move smoothly at all f-stops and that there is not an excessive amount of oil and dirt on the blades. But the smart customer will sometimes look for deals where the aperture sticks and do not work through the entire range. This is the way that the 300mm ED lenses was when I got it, with aperture blades that stick beyond an f11 setting. Again, like I care! For the astrophotographer, such high focal ratios are highly undesirable anyway. This contributed to me getting a better deal on the lens because of it. Plus, it's something that can would be fixed with a good C.L.A. anyway, important if the lens is to be used for daylight photos as well.
If you do purchase a zoom lens, make sure the zoom is firm, but not too firm (preferrably with a locking ring anyway). Likewise for the focusing ring. You don't want to take a picture where the zoom or focusing ring slides 30 minutes into the exposure; that is, unless you want a picture that looks like the starship Enterprise jumping to light speed. I think most astrophotographers have a shot like this somewhere in their collection!
8.) Know the value of the product you intend to purchase. Search past purchases of those items on eBay, Astromart, or on the Internet. Know how much you are willing to pay for a camera or lens, one that's in proper working order, before you place a bid.
9.) Ask other astrophotographers what they think of a certain camera or lens. Because more lenses have faults than others, make sure you understand how well they will work for astrophotography. The Internet is full of pictures of astro objects taken with a variety of lenses. Learn to judge the difference between a good photo, and a great one. Bloated star images in the corners and major vignetting are things to avoid. Do your research on which lenses give the best astronomical performance for the price you intend to pay.
10.) Know which focal length lenses you need for the objects you want to shoot. A good deal on a 200mm lens might be sweet, but you'll soon find that 200mm is in an area that doesn't capture a lot of good objects. Between 135mm and 300mm, most objects are too large or too small. Likewise, don't expect to take great pictures of M51, the Whirlpool Galaxy, with a 135mm lens. You need to know the angular measure that a lens provides at a given focal length and apply that to objects that are framed well within it. Doing this research will prevent you from spending money on extra lenses in a package just because you would ordinarily get a good deal. Unless you are planning to use such a camera system for daylight photography as well, many of these lenses will do you little good.
MAJOR 35mm CAMERAS
Knowing what we need in an astro camera, let's look at some (not all) of the models from the major makers of 35mm cameras throughout the years. Let's see if we can find out where the camera models became too "electronic" for our hobby and which models have the features we seek.
Nikon
The most popular Nikon camera line is their professional line of "F" series cameras. Five model classes of the F-series have been made over the years beginning with the original Nikon F in 1959 and ending with the current camera, the Nikon F5. The Nikon F had a manual shutter, as did its successor, the Nikon F2, arriving in 1971. However, the F2 (and later Nikon F models) began to use batteries to power a variety of light-metering prisms. So even though the cameras used batteries, they only powered the light-meter, a function unnecessary, actually useless, to astrophotography anyway. When the F2 was replaced by the Nikon F3 in 1980, it featured a battery powered shutter in all modes except the all important bulb mode (well, almost true...a couple of other modes, of no use to the astrophotographer, were non-powered as well). The subsequent Nikon F4 and Nikon F5 models went to full battery power and autofocus in all modes.
Therefore, any of the Nikon camera predating the F3, including those such as the Nikon FM series (1977), the Nikon FE series (1978), and the Nikkormat FT series (1965), in the less expensive, consumer oriented product lines, have some form of manual shutter/manual focus modes making them a candidate for a good astrophotography camera. It should be noted, however, that most in the FM series and the Nikkormats do not have removable focus screens nor interchangeable prisms. The FE series does have interchangeable focus screens which, in my opinion, makes this Nikon model the next best choice to the early F-series cameras among the Nikon product lines.
Regarding the F-series cameras...during their many improvements within each model type, a variety of capabilities were gradually added. You should think of it like computer software, where a minor change (representing a new capability) to a model retains the model name, but adds letters to the name to denote the new iteration. Like computer software, once a major revision of the model is done, the camera takes on a new model name. For example, the Nikon F2 camera was produced in six different incarnations over time (not including the Titanium and speciality versions). Each new F2-type came with a different, updated prism which gave the model increased capabilities when used with certain lenses. There was the original Nikon F2 (with the DE-1 prism), the Nikon F2 "Photomic" (with the DP-1 prism), the Nikon F2S (with the DP-2 prism), the Nikon F2SB (with the DP-3 prism), the Nikon F2A (with the DP-11 prism), and the Nikon F2AS (with the DP-12 prism).
Models other than the "Photomic" can be very rare and very expensive. It is not important to understand the capabilities that each prism provides (usually a difference between needle and LED metering). But what the prospective buyer should understand is that none of the prisms have an advantage over the others when it comes to astrophotography. Because of that, the least expensive F2 models (or F and F3 models) will be sufficient. But just for the record, if you can find a Nikon F2 with the original, non-metering prism (the DE-1) that came with the first version, or the DP-12 prism that came with the F2AS, and if you can get these for less than a few hundred dollars in good condition, you might be wise to purchase them. These are rare collectors items and make for a good investment. Plus, the DE-1 looks so elegant!
Incidently, you should know that all Nikon "F" bodies are the same within their own model types, being modular in design. So the version name of each model is denoted by the prism that it is equipped with. For example, you could purchase any F2 body (black or chrome), and then buy a particular prism separately since various prisms flood the used market. If you purchase the DP-12 prism and place it on any F2 body, the entire camera is referred to as the Nikon F2AS model, a version of the F2 that is much more expensive than the Photomic.
One last point: all the Nikon models mentioned can be mounted with the same lenses regardless how old or new the lenses are. Even the new, all digital SLRs like the super Nikon D1x can use the old Ai/Ai-S and non-AI lenses from the original Nikon F. Conversely, most any new lense, even autofocus lenses, can be used with older, manual focus SLRs. This backward and foreward compatibility is unique among all other 35mm camera makers and it gives a tremendous selection of lenses regardless of the model, the best of which are the ED-types made with extra-low dispersion glass. These ED lenses are some of the best lenses around.
Olympus
Among Olympus cameras, the progress of electronic development can be traced as well. The most popular, again professional, line of cameras are the "OM" series. Several models have been produced beginning with the venerable Olympus OM-1 (1972) and continuing past the powerful Olympus OM-4 (which I use as a backup to my Nikon F2) into some forgetful models (for astrophotography) like the Olympus OM-10 and the Olympus OM-PC (I've got one of these as well; the first 35mm camera I ever purchased). The OM-1 was fully manual, followed by the Olympus OM-2 which was manual in only the "B" and "T" modes, as was the aforementioned OM-4. Interestingly, the Olympus OM-3 was fully electronic. Therpredate the OM-4, except for thefore, any of the Olympus cameras that e OM-3, can be put to use for long exposure astrophotography.
The real intrigue to the Olympus OM series is their compact, light weight. Attached to a telescope, these cameras (except the OM-3 as mentioned above) add less extra weight than any other camera suitable to photography, except for maybe the Pentax MX (1976), a super-light weight camera in its own right. For this reason, and because they all have manual modes and interchangeable screens, the OMs are regarded by many as the best astro camera.
Though I feel these cameras are a great value, they are far from the best for our purposes. Their lack of a removable prism means that you will need to achieve critical focus of your camera with a method other than visual, such as with knife-edge or Ronchi devices. However, these methods of focusing are highly accurate, if not expensive, complex, and time consuming. For those who prefer this method of focusing, the Olympus OM series cameras might be just the camera you are looking for. Plus, current OM models are compatible with the same Zuiko lenses as the older ones, so the Olympus system is backward and forward compatible.
Minolta
Minolta has been making fine, innovative 35mm cameras for a long time. Older cameras, like the Minolta SR series of the early 60s and the Minolta SRT series of the late 60s, are tremendous, completely manual cameras, as are the professional Minolta X series cameras beginning in 1974. But with the aforementioned, groundbreaking Minolta XD-7 and Minolta XD-11, electronic usage began to increase. The XD-7/11 do have manual backups in bulb mode, however, so they should not be excluded as useful astrocameras. Likewise for the Minolta-made Leica models, the Leica R3, the Leica R4, and the Leica R5, all produced in 1976, the result of a brief Minolta and Leica collaboration. But beginning in 1981 with the Minolta X-700 (an otherwise very fine camera...I own one) and later in the aforementioned Maxxum series, Minolta cameras became unsuitable for astrophotography. Of all the camera lines I mentioned, and did not mention, none of the models have an interchangeable prism and most (if not all) do not have interchangeable screens (though the normal screens in many of the cameras are considered bright by normal standards). Therefore, like the Olympus OM series, any Minolta will likely require an alternative method of achieving critical focus.
Some of the Minolta Rokkor lenses are very nice, especially those geared for professionals with the need for good, fast glass. These "APO" designated lenses, especially the longer telephotos, are some of the better lenses ever made.
Pentax
It's difficult to say anything bad about Pentax 35mm cameras. They too have a longtime, and prolific, history of making compact and elegant, yet powerful cameras. But in following their timeline we can differentiate those models suitable to our purpose.
Parent company Asahi Co. of Japan produced their first SLR in 1952 with the Asahiflex I. But in 1957 they produced the first eye-level viewing SLR centered around the world's first pentaprism viewfinder. This camera, the Asahi Pentax, gave birth to the Pentax name; meaning "PENTAprism- refleX."
Prior to 1958, Pentax cameras were not available in the U.S. That changed in 1958 when Pentax cameras were distributed through Honeywell. With this agreement, and during the same year, the original Pentax K ("K" stands for "king" of the SLRs) was introduced. In 1964, Pentax developed the world's first "through-the-lens" (TTL) metering system camera, the Pentax Spotmatic.
Beginning with the Pentax K2 (1975), their first bayonet-mounted, fully automatic SLR, Pentax began to produce some worthwhile products for the astrophotographer. Between 1975 and 1976, the "K" series cameras came out in a plethora of models: the Pentax KX and Pentax KM, both in 1975; and the Pentax MX and Pentax K1000, both in 1976. Every camera in this series, to this point, have fully manual modes in the "bulb" setting, though focusing screens cannot be interchanged.
In 1977, Pentax moved to the United States and began distribution of its own cameras, dropping the Honeywell alliance. Pentax was the leading seller of SLRs during this time; the golden age for Pentax.
But with the introduction of the Pentax ME (1975), electronics took presidence. This was the first fully automatic camera, eliminating manual shutter speed control. Except for one camera, the Pentax LX (1980), all Pentax models after 1975 should be considered second-rate for astrophotography. These models include the "A"-series, the "P"-series, the "SF"-series, the "PZ"-series, and the current "ZX" and "MZ" series.
Any of the "K"-series are well-suited for astrophotography, with the K1000 model being the most widely used (because it was the lowest priced consumer model among all camera makes and models during those days) despite a lack of interchangeable focus screens and removable prisms. But the professional Pentax LX, meaning "60" in honor of Asahi's 60th anniversary, can do everything the astrophotographer needs. Taking advantage of the Super-Multi-Coated (SMC) lenses introduced in 1971 under the "Takumar" name, or the several Zeiss-compatible lenses, the Pentax LX might be be best camera available for astrophotography.
Canon
Those old enough to remember the version of Andre Agassi with hair remembers well the commericials he did for the new EOS Rebel autofocusing camera in the late 1980s. Unfortunately, any camera that he advertised will be unsuitable for astrophotography.
Perhaps the most popular Canon cameras of all-time are the consumer marketed Canon AE-1 (1976), of which I own three (don't ask why), and the Canon A-1 (1978), an elegant camera which provided 5 modes of operation. Unfortunately, these are not great cameras for astrophotography because they are fully electronic, including "B" mode. Other cameras in the "A"-series, the Canon AT-1 (1978), the Canon AV-1 (1979), and the Canon AL-1(1982) are all variations on that theme.
The best Canon model for astro-work would be their professional film camera, the Canon F-1 (1971). Still manufactured today in its F-1N incarnation, this camera has retained a manual shutter in "B" mode throughout its progression. The original version is the one to find, with full manual modes and a removable prism to boot.
Between the Canon F-1 and the rise of the "A"-series, Canon produced the "FT" and "LT" series of cameras, similar to the flagship F-1, geared toward the consumer crowd. Any of these models should be suitable for photography, though they lack both interchangeable prisms and focusing screens.
Unlike the Nikons, various models are limited in the lenses they may use. The Canon F-1 series introduced the new, and quite excellent, FD series of lenses and accessories. It incorporated a breach locking mount that differed from the R-series and FL-series lenses that came before with the old Canonflex cameras. The "A"-series and the "T"-series were also compatible with the vast FD system, including the Canon T-50 (1983) and the focus-"assisted" Canon T-80 (1985). But beginning with EOS series, the lenses were no longer backward/foreward compatible. Therefore, any Canon camera suitable for astrophotography will be limited to the FD-series lenses, some of which are the "L" types made of Super-low dispersion glasses and fluorite coatings; some of the best lenses ever made. Considering the quality of these lenses, the lack of foreward compatibility with new, auto-focus lenses should hardly be considered a negative.
An interesting sidenote: the Canon F-1 was produced in response to the Nikon F2, which dominated the photojournalist market. Instead of cutting into that market, Canon went after the professional, wild-life photography crowd. Thus, the F-1 still enjoys a dominance among this market of photographers.
CONCLUSIONS
As you can tell, I'm rather partial to Nikon cameras. Much of this comes from my childhood dreams of owning a cool looking Nikon F or Nikon F2 camera, a dream that I fulfilled three years ago. But the main reason I am high on these Nikon cameras, including the more current Nikon F3, is that they have every feature you could want in an astro camera, the only negative of which is that they are generally built like tanks! But I'll take a bit of extra weight for the satisfaction of owning a premier astrophotography, and conventional, film camera. Equipped with one of Nikon's superb, manual focus, ED lenses and a magnifying prism...it's a system that can give astro images close in quality to that of an apochromatic refractor in a similar focal length. Then again, some of these lenses are equally as expensive. Likewise, it's been said that Nikon has never produced a bad 185mm or 300mm lens. Like I said, it's all in the glass...
The next models that I would recommend would be the Canon F-1 and the Pentax LX. Both models are equipped with everything needed for astrophotography, and the Pentax LX happens to be very light weight to boot. And as mentioned before, the Canon lenses rival or surpass Nikon lenses in performance. But accessories for these cameras, especially prisms and focus screens, can be difficult to find. And these cameras, like some of the Nikons, do not come cheap.
Then of course, there is the Olympus OM-1. If you could only remove the prism on this camera it would be perfect for me since I love the ability to frame my astro objects and then focus them visually. But if I were to opt for another method of focusing, this model would be a top choice. The only negative remaining is that the Olympus Zuiko lenses are generally hind-runners to those from Nikon and Canon (though renowned astrophotographer Chuck Vaughn does use them with great success in his tri-color film images). But this camera can be purchased at a very low cost. Also, don't forget that the Olympus OM-2 and the Olympus OM-4 provide the same features if you can live with them requiring batteries for regular shutter modes other than "B."
Several other cameras I consider equal to the Olympus OM-1 because all of them have the features we need, except for the removable prism. Among Nikon, the Nikon FE and Nikon FM-2 do everything the OM-1 can do and are almost just as compact. In particular, the FM-2 can be equipped with a special 2X magnifying extension, similar to the Varimagni finder for the Olympus. Though I've said that I'm not crazy about these devices because of lower light throughput and the low magnifications using the camera's eyepiece, the FM-2's viewfinder is actually magnified at ~4x to begin with. Thus, the extension provides 8x magnication. This is just the power you need for precise focusing if the star is bright enough. Choosing a bright star to focus on first and then swinging your camera to the object you want to photograph is a good method for using such a magnifying extension despite the lesser amount of light reaching the eye.
Next in line are all the older model, manual shuttered cameras. These include the Minolta SRT and Minolta X series, the Pentax K series, the Canon FT and Canon LT series, and the early Nikon-made Nikkormat FT series. Usable because of their manual capabilities, these cameras do lack the ability to exchange focusing screens. If you already own such a camera you might consider finding a suitable screen from another manufacturer and having the camera professionally modified at your local camera shop; however, the price to do something like this might be a bit steep. It is my recommendation to simply sell these cameras and purchase a used camera with such capabilities. You'll end up with a better all-around camera and you'll spend less money to get it.
Using the above examples, it is my hope that you now understand the importance in choosing good lenses for your 35mm camera. It's also why you shouldn't choose a camera body without giving some consideration to the lenses available for it. Any lens can be made to work using certain techniques, like stopping down the aperture, or fixing problems in processing, but the idea behind a good lens is to give you the possibility of taking GREAT shots. As a beginner, you might be satisfied with the above Orion shot since your techniques will take time to refine anyway. But this shot, made by that 50mm lenses, is unfortunately typical of the results you can expect from most lens. Once again, it may shoot pretty shots during the day, but there is no more critical test of a lens' capabilities than with long exposures of the night sky.
When judging a lens by its aberrations, keep in mind that the shorter the focal length of the lens, the less important these issues become. Even though it is difficult to make a short focal length lens (sub-50mm) without aberrations when used under f4 or so, the fact that the stars become so small in such lenses tends to equal things out a bit. Therefore, most lens in these focal lengths work very well, unless of course it exhibits astigmatism, such as with the above example. As you go up in focal length, a more critical eye is required to find suitable lenses.
One final thought on lenses. Many people have zoom lenses that they would like to use for their astrophotos. Use them! But do so with an understanding of the limitations of the lens. Most zoom lenses are quite slower than their fixed, telephoto counterparts. They also contain more aberrations, more false color, and significantly more vignetting, especially at faster speeds and shorter focal lengths. Also, some zoom lenses tend to slide really easily, something you don't want to happen during a long film exposure pointed at the zenith! Therefore, if you do purchase a zoom lens, make sure it has some zoom locking mechanism to hold the slider in place.
You can certainly take some satisfying photos of the night sky with zoom lenses, just be sure you understand that you will be limited by the quality of that lens, not necessarily your techniques. This happens to be true of any lens.
ACCESSORIZING YOUR SYSTEM
Since you should be searching for a camera SYSTEM, let me make note of some of the things that you might need:
- T-rings and T-adapters - If you plan on connecting your camera to your telescope, you will need a T-ring fitted to your camera and some type of T-adapter connected to your scope (bypassing the cameras normal lenses). These two devices then connect together themselves to allow your camera to fit firmly to the scope. All cameras have a different type of bayonet mounting system specific to its make. Therefore, if you have an Olympus camera you will require an Olympus T-ring. Likewise, all scopes have a different way of connecting to the T-ring. You will require a T-adapter made for the visual back or focuser of your telescope.
- Piggyback adapter - 35mm cameras have a 1/4 - 20 threaded hole to accept tripods when used stationary. If you use the camera piggybacked atop a telescope, you will need some way to attach it. Most telescope makers sell optional mounts that will fit their scopes using the same tripod mounting socket on the camera. These mounts generally work well for cameras with lens shorter than 200mm or so. But for larger lenses, you might find these mounts to work unsatisfactorily because the extra weight of the camera and lens often causes flexure or movement in the light-weight mount. This can cause "fat" stars when the wind blows. Some larger lenses do have mounting rings so that the lens can be mounted to the adapter instead of the camera. This gives a better weight distribution and can prevent "lens bounce" on light-weight adapters, but the chances are high that you might still have problems. The solution is to use a sturdier mounting system or even a set of rings made for piggybacking a another telescope. If you are planning on using lenses greater than 200mm frequently, this is something you need to consider.
- Shutter release cables - An absolute must. Most cameras have self-timers, which can be used with some success; however, you are then limited to normal shutter speeds. In other words, if you plan on long exposures using the "B" setting, you will need a shutter release cable. Most all cables are universal, able to be used with cameras from any make. A notable exception is Nikon. The highly desirable "F"-series requires a special, threaded fitting to accommodate its shutter button. Keep this in mind when you are purchasing a cable for your Nikon F camera. Also, I recommend you get the shortest cable you can find. Long cables can easily be bumped during an exposure or blown by the wind. It could be a source vibration in your system.
- Teleconverters - Not a necessity, but certainly something that gives you extra capabilities. Akin to a barlow for a telescope, teleconverters work to multiply the focal length of your existing lenses. Common magnification of teleconverters are 1.4x, 2x, and 3x power. Beware that some teleconverters can be a source of increased vignetting and aberrations, a trade-off for extra functionality. Likewise, many teleconverters, especially those of the 2x and 3x variety, can cause a tremendous reduction of light to the eye, making focusing a bit more difficult. A teleconverter essentially doubles (in the case of 2x) both the focal length and the f-stop of the camera lens. For example, a 50mm, f1.8 lens becomes a capable 100mm, f2.6 lens with the 2x teleconverter. It is not recommended to use a teleconverter with zoom lenses, though it can be a working configuration.
A word of warning: camera makers sometimes make different models of teleconverters to match specifically to a certain range of lens focal lengths. For example, among the manual focus lens teleconverters, Nikon produced 2 different types of 1.4x teleconverters, the TC-14a and the TC-14b for their Ai-s type of lenses and their basic TC-14 1.4x teleconverter for their Ai type of lenses. The TC-14a is specifically designed for telephoto lenses less than 200mm in focal length while the TC-14b is optimized for lens 300mm and longer. Not only will a TC-14a teleconverter not physically mount to a 300mm lens, but it would not match it optically if it could, thus causing severe aberrations in the system. Make sure you get the correct type of teleconverter for your lens(es). - Eyepiece Projection Adapter - In the event that you insist on taking film shots of the moon, sun (with proper filter), and planets, one of these is a necessity. This device allows you to connect your telescope to the scope while using an eyepiece as well. Doing so gives extra magnification of the image. Total system focal length is therefore increased (and slowed) allowing magnified images of these objects to the film plane. The focal length of the eyepiece and the distance of the camera's film plane to the eyepiece determines the amount of magnification provided (the entire system focal length). Therefore, only smaller (physically) eyepieces tend to fit in the adapter. Manufacturers make these devices in both fixed and sliding varieties. The difference is that the sliding variety allows the camera to be placed anywhere behind the eyepiece, thus providing for a range of magnifications and focal ratios. The fixed version gives only one possible magnification and focal ratios per eyepiece. And by the way, you don't use your camera's own lens with an eyepiece projection adapter. It threads straight to the t-mount on your camera.
There are several (ten) guidelines for purchasing a camera system that should be heeded:
1.) Don't be afraid to purchase a camera with a broken light meter. The prices of these instruments will be very inexpensive because they are undesirable to general photographers. Likewise, any camera with the capability of removable prisms often can be purchased without a prism of any kind. This makes for a steal on the used market. The prisms often account for more than the price of camera body itself. If you are planning to add a magnifying prism or modified loupe anyway, you can save yourself some bucks.
2.) Purchase your camera equipment on eBay. Astromart is a popular place for used astronomy equipment, but the cameras, lenses, and focusing screens are generally over priced. Prices reflect a limited supply on Astromart. But the truth is that none of this equipment is scarce. Do a search on eBay for an Olympus OM-1 and you'll get around 100 hits. Prices here better reflect the demand of the camera. One on Astromart will go for $100 to $150 because its considered an "astrocamera." On eBay, it's just a used camera that nobody wants for more than $80. Likewise, the right focusing screen on Astromart will cost a pretty penny. But on eBay, the same focusing screen is just some screen that nobody uses.
There are exceptions to this rule. For example, the Nikon DW-2 6x magnifying prism for the Nikon F2 camera is considered a rare product. For this reason, these items are priced over $200 because that market has truly measured the limited supply. But on Astromart, they pop up all the time, and sometimes for a really good cost, which says a couple of things. First, a large portion of these prisms are already in the astronomy community. The rest are found among collectors of vintage cameras. Second, astrophotographers don't understand that the DW-2 is a collector's item. If they did, they'd sell it on eBay and make $50 more for it.
3.) Don't be too picky about the cosmetic condition of this used and vintage equipment. Most all cameras and lenses of this age will have a certain amount of normal wear. The wear drives down the price because vintage collectors are looking for mint or near-mint cameras.
For example, the seals that keep stray light out, located along the rear door and around the focus screen, might need to be replaced on most of these cameras anyway because the foam erodes after time, a condition known as "foam rot." Once purchased, a C.L.A. (Cleaning, Lubrication, and Adjustment) will need to be done by a local camera shop anyway, unless the camera is in satisfactory enough shape to work as is. Or, you can replace the seals yourself.
Likewise, minor brassing on the outside, especially near the strap hooks and across the base of the camera, should be expected. Scratches happen too and these scratches tend to make the camera less desirable to collectors, which is good for you, the beginning astrophotographer. You can't see the scratches and brassing in the dark anyway, right? The minor imperfections will simply drive the price down. Same thing for those cameras with broken light meters. Astrophotographers don't need them anyway.
4.) Do be aware of camera equipment with dents and major mechanical flaws. Dents are a sign that the equipment has been dropped. Not good for cameras, but especially not good for lenses. Chances are good that a dropped camera lens will exhibit optical aberrations beyond those naturally inherent in the design. Mechanically speaking, shutter speeds should be consistent throughout the entire range. The film advance lever should be smooth with all sprockets intact on the film take-up reel. The camera should be clean in the sense that it has not been exposed to dirty conditions. An excessive yellowing of the normally white indented markings on the camera could mean that the camera was in a smoker's environment or that it was exposed to moisture.
5.) Try to purchase camera components individually. Purchasing them in a package might net you a better deal, but some of the pieces are inevitably a "throw-in" item. What good are flashes, camera bags, lenses cases, filters, and hotshoes for astrophotography anyway? Don't purchase them unless they are specific to the item you want and you know you will need them.
6.) Judging the condition of camera equipment over the Internet is the most difficult part. ASK QUESTIONS! Get the assurance of the seller that the equipment will arrive in the same condition that he or she says it will be in. Get it guaranteed, if you can, or better yet, try before you buy if you are purchasing locally.
7.) Look for lenses with very few scratches on the optics, if at all, both inside and out. This is more important that the outer condition of the lenses itself. Some light scratches on the lenses might be acceptible as they probably will have a negligible effect on the end results. Just make sure the lens is priced to reflect these scratches. The same goes for stickers. I purchased my super Nikon 300mm ED lens complete with stickers, but the optics were pristine. The stickers gummed out the outside of the lens, but what did I care? Soon as I got the lens I "de-gummed" it anyway. If I sold it now I'd make a 70% profit on it!
No other condition should affect the price like good or bad glass. Many lenses will come with UV/daylight filters covering the front objective. This is a good thing. This indicates that the lens' front objective has been protected in some way by the filter.
If you are paying FULL price for a used lenses, make sure that the aperture blades move smoothly at all f-stops and that there is not an excessive amount of oil and dirt on the blades. But the smart customer will sometimes look for deals where the aperture sticks and do not work through the entire range. This is the way that the 300mm ED lenses was when I got it, with aperture blades that stick beyond an f11 setting. Again, like I care! For the astrophotographer, such high focal ratios are highly undesirable anyway. This contributed to me getting a better deal on the lens because of it. Plus, it's something that can would be fixed with a good C.L.A. anyway, important if the lens is to be used for daylight photos as well.
If you do purchase a zoom lens, make sure the zoom is firm, but not too firm (preferrably with a locking ring anyway). Likewise for the focusing ring. You don't want to take a picture where the zoom or focusing ring slides 30 minutes into the exposure; that is, unless you want a picture that looks like the starship Enterprise jumping to light speed. I think most astrophotographers have a shot like this somewhere in their collection!
8.) Know the value of the product you intend to purchase. Search past purchases of those items on eBay, Astromart, or on the Internet. Know how much you are willing to pay for a camera or lens, one that's in proper working order, before you place a bid.
9.) Ask other astrophotographers what they think of a certain camera or lens. Because more lenses have faults than others, make sure you understand how well they will work for astrophotography. The Internet is full of pictures of astro objects taken with a variety of lenses. Learn to judge the difference between a good photo, and a great one. Bloated star images in the corners and major vignetting are things to avoid. Do your research on which lenses give the best astronomical performance for the price you intend to pay.
10.) Know which focal length lenses you need for the objects you want to shoot. A good deal on a 200mm lens might be sweet, but you'll soon find that 200mm is in an area that doesn't capture a lot of good objects. Between 135mm and 300mm, most objects are too large or too small. Likewise, don't expect to take great pictures of M51, the Whirlpool Galaxy, with a 135mm lens. You need to know the angular measure that a lens provides at a given focal length and apply that to objects that are framed well within it. Doing this research will prevent you from spending money on extra lenses in a package just because you would ordinarily get a good deal. Unless you are planning to use such a camera system for daylight photography as well, many of these lenses will do you little good.
MAJOR 35mm CAMERAS
Knowing what we need in an astro camera, let's look at some (not all) of the models from the major makers of 35mm cameras throughout the years. Let's see if we can find out where the camera models became too "electronic" for our hobby and which models have the features we seek.
Nikon
The most popular Nikon camera line is their professional line of "F" series cameras. Five model classes of the F-series have been made over the years beginning with the original Nikon F in 1959 and ending with the current camera, the Nikon F5. The Nikon F had a manual shutter, as did its successor, the Nikon F2, arriving in 1971. However, the F2 (and later Nikon F models) began to use batteries to power a variety of light-metering prisms. So even though the cameras used batteries, they only powered the light-meter, a function unnecessary, actually useless, to astrophotography anyway. When the F2 was replaced by the Nikon F3 in 1980, it featured a battery powered shutter in all modes except the all important bulb mode (well, almost true...a couple of other modes, of no use to the astrophotographer, were non-powered as well). The subsequent Nikon F4 and Nikon F5 models went to full battery power and autofocus in all modes.
Therefore, any of the Nikon camera predating the F3, including those such as the Nikon FM series (1977), the Nikon FE series (1978), and the Nikkormat FT series (1965), in the less expensive, consumer oriented product lines, have some form of manual shutter/manual focus modes making them a candidate for a good astrophotography camera. It should be noted, however, that most in the FM series and the Nikkormats do not have removable focus screens nor interchangeable prisms. The FE series does have interchangeable focus screens which, in my opinion, makes this Nikon model the next best choice to the early F-series cameras among the Nikon product lines.
Regarding the F-series cameras...during their many improvements within each model type, a variety of capabilities were gradually added. You should think of it like computer software, where a minor change (representing a new capability) to a model retains the model name, but adds letters to the name to denote the new iteration. Like computer software, once a major revision of the model is done, the camera takes on a new model name. For example, the Nikon F2 camera was produced in six different incarnations over time (not including the Titanium and speciality versions). Each new F2-type came with a different, updated prism which gave the model increased capabilities when used with certain lenses. There was the original Nikon F2 (with the DE-1 prism), the Nikon F2 "Photomic" (with the DP-1 prism), the Nikon F2S (with the DP-2 prism), the Nikon F2SB (with the DP-3 prism), the Nikon F2A (with the DP-11 prism), and the Nikon F2AS (with the DP-12 prism).
Models other than the "Photomic" can be very rare and very expensive. It is not important to understand the capabilities that each prism provides (usually a difference between needle and LED metering). But what the prospective buyer should understand is that none of the prisms have an advantage over the others when it comes to astrophotography. Because of that, the least expensive F2 models (or F and F3 models) will be sufficient. But just for the record, if you can find a Nikon F2 with the original, non-metering prism (the DE-1) that came with the first version, or the DP-12 prism that came with the F2AS, and if you can get these for less than a few hundred dollars in good condition, you might be wise to purchase them. These are rare collectors items and make for a good investment. Plus, the DE-1 looks so elegant!
Incidently, you should know that all Nikon "F" bodies are the same within their own model types, being modular in design. So the version name of each model is denoted by the prism that it is equipped with. For example, you could purchase any F2 body (black or chrome), and then buy a particular prism separately since various prisms flood the used market. If you purchase the DP-12 prism and place it on any F2 body, the entire camera is referred to as the Nikon F2AS model, a version of the F2 that is much more expensive than the Photomic.
One last point: all the Nikon models mentioned can be mounted with the same lenses regardless how old or new the lenses are. Even the new, all digital SLRs like the super Nikon D1x can use the old Ai/Ai-S and non-AI lenses from the original Nikon F. Conversely, most any new lense, even autofocus lenses, can be used with older, manual focus SLRs. This backward and foreward compatibility is unique among all other 35mm camera makers and it gives a tremendous selection of lenses regardless of the model, the best of which are the ED-types made with extra-low dispersion glass. These ED lenses are some of the best lenses around.
Olympus
Among Olympus cameras, the progress of electronic development can be traced as well. The most popular, again professional, line of cameras are the "OM" series. Several models have been produced beginning with the venerable Olympus OM-1 (1972) and continuing past the powerful Olympus OM-4 (which I use as a backup to my Nikon F2) into some forgetful models (for astrophotography) like the Olympus OM-10 and the Olympus OM-PC (I've got one of these as well; the first 35mm camera I ever purchased). The OM-1 was fully manual, followed by the Olympus OM-2 which was manual in only the "B" and "T" modes, as was the aforementioned OM-4. Interestingly, the Olympus OM-3 was fully electronic. Therpredate the OM-4, except for thefore, any of the Olympus cameras that e OM-3, can be put to use for long exposure astrophotography.
The real intrigue to the Olympus OM series is their compact, light weight. Attached to a telescope, these cameras (except the OM-3 as mentioned above) add less extra weight than any other camera suitable to photography, except for maybe the Pentax MX (1976), a super-light weight camera in its own right. For this reason, and because they all have manual modes and interchangeable screens, the OMs are regarded by many as the best astro camera.
Though I feel these cameras are a great value, they are far from the best for our purposes. Their lack of a removable prism means that you will need to achieve critical focus of your camera with a method other than visual, such as with knife-edge or Ronchi devices. However, these methods of focusing are highly accurate, if not expensive, complex, and time consuming. For those who prefer this method of focusing, the Olympus OM series cameras might be just the camera you are looking for. Plus, current OM models are compatible with the same Zuiko lenses as the older ones, so the Olympus system is backward and forward compatible.
Minolta
Minolta has been making fine, innovative 35mm cameras for a long time. Older cameras, like the Minolta SR series of the early 60s and the Minolta SRT series of the late 60s, are tremendous, completely manual cameras, as are the professional Minolta X series cameras beginning in 1974. But with the aforementioned, groundbreaking Minolta XD-7 and Minolta XD-11, electronic usage began to increase. The XD-7/11 do have manual backups in bulb mode, however, so they should not be excluded as useful astrocameras. Likewise for the Minolta-made Leica models, the Leica R3, the Leica R4, and the Leica R5, all produced in 1976, the result of a brief Minolta and Leica collaboration. But beginning in 1981 with the Minolta X-700 (an otherwise very fine camera...I own one) and later in the aforementioned Maxxum series, Minolta cameras became unsuitable for astrophotography. Of all the camera lines I mentioned, and did not mention, none of the models have an interchangeable prism and most (if not all) do not have interchangeable screens (though the normal screens in many of the cameras are considered bright by normal standards). Therefore, like the Olympus OM series, any Minolta will likely require an alternative method of achieving critical focus.
Some of the Minolta Rokkor lenses are very nice, especially those geared for professionals with the need for good, fast glass. These "APO" designated lenses, especially the longer telephotos, are some of the better lenses ever made.
Pentax
It's difficult to say anything bad about Pentax 35mm cameras. They too have a longtime, and prolific, history of making compact and elegant, yet powerful cameras. But in following their timeline we can differentiate those models suitable to our purpose.
Parent company Asahi Co. of Japan produced their first SLR in 1952 with the Asahiflex I. But in 1957 they produced the first eye-level viewing SLR centered around the world's first pentaprism viewfinder. This camera, the Asahi Pentax, gave birth to the Pentax name; meaning "PENTAprism- refleX."
Prior to 1958, Pentax cameras were not available in the U.S. That changed in 1958 when Pentax cameras were distributed through Honeywell. With this agreement, and during the same year, the original Pentax K ("K" stands for "king" of the SLRs) was introduced. In 1964, Pentax developed the world's first "through-the-lens" (TTL) metering system camera, the Pentax Spotmatic.
Beginning with the Pentax K2 (1975), their first bayonet-mounted, fully automatic SLR, Pentax began to produce some worthwhile products for the astrophotographer. Between 1975 and 1976, the "K" series cameras came out in a plethora of models: the Pentax KX and Pentax KM, both in 1975; and the Pentax MX and Pentax K1000, both in 1976. Every camera in this series, to this point, have fully manual modes in the "bulb" setting, though focusing screens cannot be interchanged.
In 1977, Pentax moved to the United States and began distribution of its own cameras, dropping the Honeywell alliance. Pentax was the leading seller of SLRs during this time; the golden age for Pentax.
But with the introduction of the Pentax ME (1975), electronics took presidence. This was the first fully automatic camera, eliminating manual shutter speed control. Except for one camera, the Pentax LX (1980), all Pentax models after 1975 should be considered second-rate for astrophotography. These models include the "A"-series, the "P"-series, the "SF"-series, the "PZ"-series, and the current "ZX" and "MZ" series.
Any of the "K"-series are well-suited for astrophotography, with the K1000 model being the most widely used (because it was the lowest priced consumer model among all camera makes and models during those days) despite a lack of interchangeable focus screens and removable prisms. But the professional Pentax LX, meaning "60" in honor of Asahi's 60th anniversary, can do everything the astrophotographer needs. Taking advantage of the Super-Multi-Coated (SMC) lenses introduced in 1971 under the "Takumar" name, or the several Zeiss-compatible lenses, the Pentax LX might be be best camera available for astrophotography.
Canon
Those old enough to remember the version of Andre Agassi with hair remembers well the commericials he did for the new EOS Rebel autofocusing camera in the late 1980s. Unfortunately, any camera that he advertised will be unsuitable for astrophotography.
Perhaps the most popular Canon cameras of all-time are the consumer marketed Canon AE-1 (1976), of which I own three (don't ask why), and the Canon A-1 (1978), an elegant camera which provided 5 modes of operation. Unfortunately, these are not great cameras for astrophotography because they are fully electronic, including "B" mode. Other cameras in the "A"-series, the Canon AT-1 (1978), the Canon AV-1 (1979), and the Canon AL-1(1982) are all variations on that theme.
The best Canon model for astro-work would be their professional film camera, the Canon F-1 (1971). Still manufactured today in its F-1N incarnation, this camera has retained a manual shutter in "B" mode throughout its progression. The original version is the one to find, with full manual modes and a removable prism to boot.
Between the Canon F-1 and the rise of the "A"-series, Canon produced the "FT" and "LT" series of cameras, similar to the flagship F-1, geared toward the consumer crowd. Any of these models should be suitable for photography, though they lack both interchangeable prisms and focusing screens.
Unlike the Nikons, various models are limited in the lenses they may use. The Canon F-1 series introduced the new, and quite excellent, FD series of lenses and accessories. It incorporated a breach locking mount that differed from the R-series and FL-series lenses that came before with the old Canonflex cameras. The "A"-series and the "T"-series were also compatible with the vast FD system, including the Canon T-50 (1983) and the focus-"assisted" Canon T-80 (1985). But beginning with EOS series, the lenses were no longer backward/foreward compatible. Therefore, any Canon camera suitable for astrophotography will be limited to the FD-series lenses, some of which are the "L" types made of Super-low dispersion glasses and fluorite coatings; some of the best lenses ever made. Considering the quality of these lenses, the lack of foreward compatibility with new, auto-focus lenses should hardly be considered a negative.
An interesting sidenote: the Canon F-1 was produced in response to the Nikon F2, which dominated the photojournalist market. Instead of cutting into that market, Canon went after the professional, wild-life photography crowd. Thus, the F-1 still enjoys a dominance among this market of photographers.
CONCLUSIONS
As you can tell, I'm rather partial to Nikon cameras. Much of this comes from my childhood dreams of owning a cool looking Nikon F or Nikon F2 camera, a dream that I fulfilled three years ago. But the main reason I am high on these Nikon cameras, including the more current Nikon F3, is that they have every feature you could want in an astro camera, the only negative of which is that they are generally built like tanks! But I'll take a bit of extra weight for the satisfaction of owning a premier astrophotography, and conventional, film camera. Equipped with one of Nikon's superb, manual focus, ED lenses and a magnifying prism...it's a system that can give astro images close in quality to that of an apochromatic refractor in a similar focal length. Then again, some of these lenses are equally as expensive. Likewise, it's been said that Nikon has never produced a bad 185mm or 300mm lens. Like I said, it's all in the glass...
The next models that I would recommend would be the Canon F-1 and the Pentax LX. Both models are equipped with everything needed for astrophotography, and the Pentax LX happens to be very light weight to boot. And as mentioned before, the Canon lenses rival or surpass Nikon lenses in performance. But accessories for these cameras, especially prisms and focus screens, can be difficult to find. And these cameras, like some of the Nikons, do not come cheap.
Then of course, there is the Olympus OM-1. If you could only remove the prism on this camera it would be perfect for me since I love the ability to frame my astro objects and then focus them visually. But if I were to opt for another method of focusing, this model would be a top choice. The only negative remaining is that the Olympus Zuiko lenses are generally hind-runners to those from Nikon and Canon (though renowned astrophotographer Chuck Vaughn does use them with great success in his tri-color film images). But this camera can be purchased at a very low cost. Also, don't forget that the Olympus OM-2 and the Olympus OM-4 provide the same features if you can live with them requiring batteries for regular shutter modes other than "B."
Several other cameras I consider equal to the Olympus OM-1 because all of them have the features we need, except for the removable prism. Among Nikon, the Nikon FE and Nikon FM-2 do everything the OM-1 can do and are almost just as compact. In particular, the FM-2 can be equipped with a special 2X magnifying extension, similar to the Varimagni finder for the Olympus. Though I've said that I'm not crazy about these devices because of lower light throughput and the low magnifications using the camera's eyepiece, the FM-2's viewfinder is actually magnified at ~4x to begin with. Thus, the extension provides 8x magnication. This is just the power you need for precise focusing if the star is bright enough. Choosing a bright star to focus on first and then swinging your camera to the object you want to photograph is a good method for using such a magnifying extension despite the lesser amount of light reaching the eye.
Next in line are all the older model, manual shuttered cameras. These include the Minolta SRT and Minolta X series, the Pentax K series, the Canon FT and Canon LT series, and the early Nikon-made Nikkormat FT series. Usable because of their manual capabilities, these cameras do lack the ability to exchange focusing screens. If you already own such a camera you might consider finding a suitable screen from another manufacturer and having the camera professionally modified at your local camera shop; however, the price to do something like this might be a bit steep. It is my recommendation to simply sell these cameras and purchase a used camera with such capabilities. You'll end up with a better all-around camera and you'll spend less money to get it.
A couple of camera bodies that might be intriguing were made by other manufacturers. Yashica makes some good manual cameras, like the Yashica YX-3 for example, and they even have the ability to use some of the Contax lenses made by Zeiss. Ricoh, Mayima-Sekor, and Chinon also make decent, fully manual cameras with some of the capabilities we need in an astro camera. Some, like my old Chinon CS, shown at right, even have screw mounted lenses, so a T-ring isn't necessary. The aforementioned Leica Rseries cameras, made in collaboration with Minolta, might also be suitable. Likewise, if you can find a Contax RTS for a reasonable price, you might have something to work with.
I'll leave you to research some of these models, and other cameras I did not mention, but some of them, like the Leicas, will not be cheap!
I'll leave you to research some of these models, and other cameras I did not mention, but some of them, like the Leicas, will not be cheap!
