Got a Sankyo Koki 135 f3.5 on a whim at a pawn shop for 10 bucks.....turns out it has a 16-blade aperture. Not bad, but it adapts wonderfully to my 5D digital and my EOS film system

I had my eyes on some Carl Zeiss Jena glass, specifically the 50 2.8. What other diamonds in the rough am I looking for?