I've seen some really stunning with 50mm f4 macros posted on these forums. I wonder how it compares to the modern DFA 50mm f2.8 macro??
On topic: I have only a few 50mm lenses. The
M 50mm f1.7 seems to be quite enough. I also have:
Industar 50-2, which is a tessar ripoff and has quite nice rendering, but edges are not very good. It also has an odd preset aperture system and its base is not wide enough to cover the Pentax K-mount, so buying a flanged adapter might be the better option. I like this lens. Maybe I shouldn't, but I do. I think it was a great buy for the $25.
Miranda 50mm f1.9. Somehow this lens renders things very.. delicately. Not super sharp, completely plastic, but its rendering is very different from the "good" lenses and the typical Soviet bokeh lenses. I keep it because I wouldn't get much selling it.
And then there is the
Helios 44-2. Not really 50mm, but there are rumours the Pentax 50mm are actually 53mm, so its all the same ballpark. I don't have to say much about the Helios 44-2, its a well known lens on these forums, but I don't use it very much. Very sharp in centre when stopped down, though! Wide open, in my opinion, its nearly useless, not sharp enough.
Edit: I hope some of the Nifty Fifty collectors post in this thread!
There are at least a couple on this forum that I know of