I've been collecting this lens for a while now because it's simply amazing--the best value 50mm IMO--but I can't justify owning three of them anymore. So I'm going to sell these two, each of which is flawed in some way. Both use the Contax/Yashica C/Y mount. Yashica ML 50mm f/2 #1: This was is actually the sharpest copy I have, but the focus barrel is a little rough. It's nothing that actually affects how you take pictures--you can still adjust focus perfectly, even making micro-adjustments--it's just not as smooth as you'd like. Everything else is excellent-no haze, fungus, scratches; aperture blades are oil-free and snappy. Comes with front and rear caps. Price is $20 + shipping in CONUS. SOLD Yashica ML 50mm f/2 #2: This one focuses as smooth as butter but is a tad less sharp wide-open. By f/2.8 it's just as sharp as the others. The biggest issue with this copy is that the filter threads are a bit dinged, which prevents it from accepting filters. (Actually you can wedge one on if you're careful . . . I've taken plenty of pictures with a ND filter. But filters don't spin on and off easily, that's for sure.) The barrel is a little worn, but everything works perfectly. Optically it's clean--no scratches, haze, or fungus; aperture blades are clean and snappy. This one only comes with a rear cap. (If you look carefully at the last picture you can see the filter dings . . . there are three of them.) Price is $10 + shipping in CONUS. I'm not a big seller in here (but I do have feedback!) but I've sold lots of stuff in eBay under the username Kilauea33701, where I have a 100% feedback rating.