Hi,
At the moment I have the following 50's to play with... Minolta 55mm f1.7 MC, 50mm f1.4 MD, 50mm f1.2 MD, Olympus 50mm f1.8 and f1.4, Canon FD 50mm f1.4, Sigma 50mm f2.8 macro.
Of these I'd say that the Minolta f1.4 MD is the best, it's pretty sharp and has less optical nasties at wide apertures and it has a touch more contrast but some people like the lower contrast look. Next is probably the Oly f1.8 with the FD next and then the Oly f1.4. I'd say that the Minolta f1.2 is optically the poorest 50mm I have but I just like the look
The Sigma macro BTW is IMO quite excellent.
I'm still playing with the 55mm f1.7 MC but so far I do like the look it gives. Sharpness wise, I post stuff here from my pc at quality 9 or 10 so I'm not too sure how that affects the quality and sharpness but sharpness doesn't seem to be an issue when viewing full images at full quality and 100% on my screen. Even at f1.7 I'd say it's acceptable. I think these MC's have less good coatings and probably a different optical make up to the later MD's, I'd say that the MD f1.7 I had a few years ago and sold and the f1.4 I still have both have a more modern look than the MC, if you can follow what I mean
but the 55mm f1.7 does seem to have a different look so I suppose what you go for depends on what you want. If you want a more modern clinical look I'd say go for an MD and if you want more character go for an earlier MC
Oh, and for my recent postings here I haven't done any vignetting or distortion corrections.
I'd say they're deffo worth looking at