If you are a film astrophotographer, you really ought to take a close look at this camera. I have used one of these for years and get consistently better results than with my more expensive cameras. This camera was made in East Germany and was orginally a waist view SLR. I have removed all the viewfinder linkage, frosted glass plate, etc, and installed a Unitron 25mm eyepiece that has been precisely focused. When you look through this eyepiece, what you see is what you get. No guesswork on focus. There is no need for varimag-finders or special screens. The image is formed just as it is in any other eyepiece in your scope, and the position of the eyepiece is akin to having a built-in star diagonal.
As well, the mirror will lock up separately before firing the shutter. The shutter on this one is air tight and I have shot solar with it through my h-alpha filter system. The shutter speeds seem accurate. It uses a standard old shutter release cable if you're doing remote stuff. The condition of the camera overall is remarkable, especially considering it's age. It comes with the correct T-Adapter, and I will include a 1.25" adapter that isn't the best, but you're welcome to it.
$100 shipped in the United States.