I'd say buy it, but make sure it's cheap. One thing unique about the K 55mm lenses is, that on K bodies, you can keep your off-eyepiece eye open, and both eyes appear to be looking at the same view.
That trick doesn't work quite as well with, say, an MX and an M50mm, at least not in my experience.
People who pick apart differences in Pentax 50s are picking apart pretty small differences. I think the major discriminating factor is lens speed, and not everybody would routinely have need for something faster than 2.0.
m.s.gill wrote:
What about SMC Pentax 55mm F/2 (K 55/2 # 1769*** which is reported better than SMC Pentax 50 mm F/1.2 in "My Lens Resolution Test Results". One is lying filter screw damaged and small scratches on front elements here in a shop of Lahore Pakistan but owner is not willing to make me a test. Any advice/comments from the largest folks around the planet mailing list will help to grab this normal lens.
