I just got this in the mail about 45 minutes ago in trade for one of my russian cameras. (Traded a Zenit-11 for it) Soon as the lens warmed up (came in from the freezing cold all day in the mailbox) I tried it on my Canon P to make sure the back element didn't bump into the light baffles, and fits like a charm. Anyways heres some quick second shots off the top of my desk as I sit here on the computer. Can't wait to shoot this thing tomorrow. On my Canon P, its a little shorter than my Canon 50mm f/1.8, but the diameter is wider than the front of the 50mm. The back of the lens focused at infinity. Note how its within a few mm of the light baffles and how close it gets to the shutter curtains.