The use of obsolete Contax / Yashica lenses on Canon EOS bodies is relatively common, but some exotic combinations of lenses and bodies are little documented and their compatibility unknown. I have now had some experience adapting two C/Y lenses on two Canon EOS bodies and I can report the results, unfortunately not enthusiastically.
|Camera||Lens||Result: mirror||Result: meter|
|EOS 5||Carl Zeiss Tessar 45/2.8||hits the lens||off about 1-1.5 EV|
|EOS 5||Carl Zeiss Sonnar 135/2.8||hits the lens||off about 1-1.5 EV|
|EOS 1n||Carl Zeiss Tessar 45/2.8||hits the lens||OK|
|EOS 1n||Carl Zeiss Sonnar 135/2.8||clear||OK|
By the way, the EOS 5 has the undeniable advantage of a very silent operation over EOS 1n but, besides this, the 1n is clearly a better camera.