Digital Cameras
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Those who use a Questar for telescopic photography today don’t have quite as many constraints in terms of camera choice as did individuals decades ago. In the 1950s, rangefinder cameras were at the peak of their popularity, and single-lens reflex (SLR) cameras had yet to gain widespread acceptance. As early as 1958, Braymer advised using an SLR with ground glass focusing screen, focal plane shutter, and removable lens. By advocating for the SLR at a time when rangefinder cameras were at their peak, he demonstrated how much he was at the forefront of photographic technology at the time.
But photography has obviously come a long way since the days of the Questar-modified Praktina and Nikon F. In the 2000s, film cameras gave way to DSLRs, digital point-and-shoot cameras, and, for most individuals, the omnipresent smartphone and its increasingly sophisticated camera.
In more recent years, mirrorless digital camera technology began edging out DSLRs for many serious photographers. At the time of writing (early 2023), many argue that mirrorless cameras represent the frontier of development in digital photography.
I can’t claim a vast amount of insight into the multitude of mirrorless digital cameras on the market. But my scrapy and intrepid Canon EOS M200 has given me enough experience to share some thoughts that may be useful to others who are interested in using their Questar telescope as a photographic instrument. Much of what I have to say about my M200 applies to countless other mirrorless cameras available today.
When I bought my M200 in the autumn of 2020, I had been a Canon user for years, albeit only with various point-and-shoot models. Unwilling to risk trying out the equipment other manufacturers offered and spending hundreds of dollars to do so, I opted to stay with something familiar. It didn’t hurt that the M200 was one of the least expensive options for interchangeable lens cameras. Its size seemed ideally suited for my intended application with my Questar, and it seemed like a great way to upgrade from my capable but tired Canon PowerShot S110 I had been using for years.
Camera Coupling
Connecting my M200 camera to my Questar is straightforward. With a Questar camera coupler, I also use a Canon M-to-M42 lens adapter. My inexpensive Fotasy adapter, which is available at the time of writing for around $10, is well machined. After screwing it into the Questar coupler, the camera securely connects to the adapter with a satisfying and definite “click” sound.
The camera’s small size and minimal weight—with battery and memory card, Canon’s specifications indicate it weighs a mere 10.55 ounces or 299 grams—exerts little if any force onto the back of the scope. The entire assembly is well balanced. Even with my recently serviced Questar whose up-down motion is smooth and free of excessive friction, I never have to engage the declination lock when the camera is attached to the scope.
Sensor
I have to confess that I had no experience whatsoever with digital cameras with interchangeable lenses when I bought my M200. In hindsight, I feel a bit lucky to have stumbled upon a camera whose other features were well suited to the Questar telescope, features I realized only after I bought the camera.
Its APS-C sensor with 1.6x crop factor fits well inside the circle of illumination with only minimal vignetting on my 1962 Questar that was converted to the wide field construction not long after its initial manufacture date. On another 1962 Questar I have, one in all-original condition including its older narrow field construction, vignetting is far more apparent especially when the camera is closely coupled with the camera. Using extension tubes helps to limit that vignetting at the cost of a slower exposure.
Those with full-frame sensors may find significantly increased amounts of vignetting. Even if you enjoy the benefit of a Questar with wide field construction, you may find that the fully illuminated image circle isn’t wide enough to cover the entire sensor.
Viewing Screen
The M200’s flip-up view screen offers excellent ergonomics when the scope is pointed at both terrestrial subjects and celestial ones. After having tried my Canon EOS M50 mirrorless camera, a close cousin to the M200, on my Questar, I found that the M50’s articulating screen isn’t quite as well suited for use with a telescope like the Questar as the M200 is.
To focus the scope, the camera’s magnifier tool allows me to zoom in on my subject by a factor of 5 and 10x, making it quite easy to nail focus sharply. There is none of the ambiguity that I often find when I try to focus the scope with a film camera attached.
Shutter
Although Canon’s specifications don’t expressly indicate this, I’m reasonably certain that the M200 features an electronic front curtain shutter (EFCS). By observing the behavior of the camera without a lens attached and with shutter speed set to something slow like one second, what I see and hear upon pressing the shutter button is a soft click upon beginning the exposure. When the exposure is complete, I see the quick action of a physical shutter curtain up and back down. By all accounts, this is precisely how an EFCS shutter operates. By minimizing shutter shock vibrations, one also minimizes the blurred images that result from those vibrations.
On a camera with a fully mechanical shutter, on the other hand, what I would see is a physical shutter curtain going up and down both at the beginning and the end of the exposure. That first up and down motion is precisely the kind of jarring force that jerks the camera right when an exposure is being made, something that the telescopic photographer desperately wants to avoid.
To get the shutter to fire, there’s one potential hangup that’s easy to fix but that is also not well documented. By default, Canon sets the camera to prevent its shutter from operating without a lens attached. Since the lens adapter has no electrical contacts, the camera body thinks there’s no lens attached, and the shutter won’t operate as a result. To fix this, you have to go into setup menu #5, select “Custom Functions (C.Fn),” and enable option #5, “Release shutter w/o lens.” Again, it’s very easy to do, but the option is somewhat buried in the menu system.
The Bluetooth remote-control feature of Canon’s Camera Connect iOS app eliminates the need for any kind of old-fashioned shutter release cable. The last thing you want to do is work the shutter button on the camera itself and jerk the entire assembly precisely when making an exposure. The large size of the button enables me to fire the shutter without having to hunt around for it when I’m using my Questar and camera in the dark.
Shooting Mode
As is the case with any kind of adapted lens that lacks electrical contacts, one must use Aperture Priority mode to automate shutter speed. Going for Manual mode is another option if you want full control over your exposure time. In the past, I’ve taken images of the Moon using Program mode, and I never saw much of a difference. But with my various fully-manual lenses, the camera seems to get confused about picking the right shutter speed when I use it in Program mode.
Shutter Priority mode is useless because the camera has no way to set aperture when it’s attached to a telescope with a fixed aperture.
Sample Images
Once I got everything set up, I began having a lot of fun with my Canon EOS M200 and my Questar. Things really got interesting after I got my 1962 with wide field conversion serviced and had a new optics set installed in it (more details about that here).
Daytime Subjects
Finding daytime terrestrial subjects to shoot was one great way to get acquainted with the camera and scope combo. In my region in the Pacific Northwest, we have western fence lizards who like to make their home in our backyard. As they bask in the sun, they stay perfectly still and make ideal subjects for a telescope that effectively acts like a camera lens set to f/16.
Out of the many photographs I’ve taken of these little lizards, this is one of my favorites, one I took with my updated Questar from a distance of around 20 feet. My shutter speed was 1/40 second, and I set my ISO to 200 to minimize noise:
This is a 100% crop of the same image—note the incredible resolution in the lizard’s eyelid and in the scales below its mouth:
Somewhat more challenging daytime subjects in the backyard include hummingbirds. On first glance, one might not think that the fast motion of hummingbird wings could be within the grasp of an f/16 instrument. But thanks to the reasonably good performance of modern digital cameras operating at higher ISO settings, they are.
I shot this photograph of a rufous hummingbird in good morning light from a distance of around 20 feet using a shutter speed of 1/1000 second at ISO 3200:
This is actually the best of around 100 images I took that morning. Especially with hummingbirds, I’ve found the M200’s continuously shooting shutter drive mode to be essential. To get those few keeper images, I’ll shoot several images per second when hummingbird is at the feeder and throw away all but a handful.
A bit later after I took the above image, another hummingbird settled down on a tomato cage next to my feeder long enough for me to refocus, drop my shutter speed to 1/50 second and my ISO to 200, and take a single picture before it flew off:
This is a 100% crop of the same image:
Especially with the benefit of an updated optics set, getting incredibly well resolved images of these small birds is relatively easy.
Nighttime Subjects
As far as celestial targets are concerned, there is no easier one to shoot than the Moon. I shot this image at 1/4-second shutter speed with my ISO set to 100:
Here is a 100% crop of that same image at the lunar terminator:
Counterintuitively, I’ve found that shooting the Moon at a low ISO setting of 100 or 200 yields better image quality even under poorer seeing conditions than a higher ISO setting. To my eye, the increased noise of those higher settings cancels out whatever benefit they may bring in terms of being able to use faster shutter speeds, which in theory would freeze the shimmering motion that is caused by the kind of atmospheric turbulence that is visually obvious in the eyepiece.
Only the brightest deep space objects are within easy grasp of a telescope operating photographically at f/16. I have had the most success with perhaps the best of all showcase objects, the Great Orion Nebula (M42). I shot this image with my M200 when the nebula was 46° west of the meridian at an altitude of about 30°, or about 12° below this object’s highest altitude at the meridian. My shutter speed was 30 seconds and my ISO was set very high at 12,800:
I’ve tried imaging M42 with my M200 at an ISO of 25,600 in order to reduce my shutter speed to 15 seconds, but I have found that the level of noise at those settings is unacceptably high. At lower ISO settings, I have to increase exposure time, and tracking for periods longer than 30 seconds become problematic. Generally speaking, I’ve settled on 30-second exposures at ISO 12,800 as the best compromise when imaging M42.
There is no doubt that dedicated astronomical imaging cameras are better suited to the specialized task of imaging celestial objects. Likewise, a faster telescope with more aperture will surely lead to better results. But for those who appreciate the beauty of having a self-contained device that’s simple and doesn’t require a laptop or other external device, mirrorless digital cameras like my Canon EOS M200 are a great option.