After knowing that my wife has had a 500mm f/8 Kalimar lens ever since we met, I never thought about using it until recently!
You see, she and I were both Nikon SLR folks so the lens had a Nikon mount. Since going digital, I now use Canon dSLRs so didn't think that the lens would work. One day, I happened across a Nikon to EOS lens adapter on the web and bought one to use with the Nikkor 50mm f/1.4. That actually works very well. The Nikkor 50mm is a manual focus lens that's built like a tank and looks weird, but works well on my Canon 30D. However, it refused to work with the Kalimar 500mm lens.
Switch to near history and I bought a very inexpensive, but irresistible 400mm refractor lens from my favorite astronomy equipment site: astromart.com. It is a 400mm f/6.3 Vemar lens. I know, I know... what the heck is a Vemar lens? Well, it's a fairly well built, but so far as I can tell, medium to low optical quality lens at a price that I couldn't refuse. $30! It looks quite nice on the 30D.
The Vemar 400mm is a T-thread or T-mount lens and so needed a T-mount adapter. I thought I had one from one of my telescope adapter/lens combinations, but it didn't work. When I went online to look for one, I thought about the Kalimar 500mm f/8! It also seemed to have an interchangeable mount so I ordered two T-mount to Canon lens adapters. When they arrived, one went on the Vemar and one went on the Kalimar. The Kalimar is very compact and also looks good mounted to my 30D.
I've only had them out one night to shoot the moon and the results are mixed so far. I need to pixel-peep and tweak the photos that I took with these lenses.
More soon and clear skies!