@bozaman - Despite my pouring of cold water on your enthusiasm for manual lenses, I confess that I do have a few old OM Zuiko examples and an OM to L converter. I’ve done some playing around and this is my analysis:
- Late 50mm f1.8 - actually very good. Acceptably sharp into the corners even wide open. Good contrast and colours. All it needs is AF to challenge my Panasonic 50mm f1.8 which is twice the size but performs beautifully!
- 24mm f2.8 - not sure of the age, but it's not a great performer. Centre of the frame is OK at f2.8, but the edges and corners are awful. By about f11 the sharpness across the frame is almost acceptable, but not quite.
- 100mm f2.8 - another late model, which I actually bought "new" in a closeout sale. It had been sat in its box unsold since the 1980s! And it's another great performer - quite the lens (not that I do any).
- 135mm f3.5 - just awful.
It's fun to play with these from time to time, but I'd never do anything serious with them!