Originally posted by Sagitta The Sears to look for is the one with the 49mm filter threads. It tagged along when I bought my 135mm macro, (I was after the 135, not what I believed was a redundant 50mm) and I was shocked to realize it was better than the 52mm filter version.
Shorter minimum focus throw, half stop aperture clicks, and maxxes out at f/22 as opposed to f/16.
You can spot it because it lacks the red on the front of the lens that its brother has. Its the top center lens in this shot. Second shot is the aperture stops.
Quite the collection of Sears lenses you have there!
Interesting. You know, I think I have
yet another version of the Sears 50mm f/1.7 with 52mm filter ring than what you have pictured here. The front element on mine is quite deeply recessed, unlike the lenses you have pictured here. It's bigger than my SMC-M 50/1.4.
Tonight after work, I'll double check... maybe take a few pics and upload them here for comparison sake.
Anyway, the 49mm filter thread version indeed sounds preferable. Even if everything else were the same, the filter thread alone makes it fit into the Pentax M system better. As it is, I have a 52mm->58mm step-up ring semi-permanently mounted on there for my 58mm filter collection.