Originally posted by tennjed best 50mm macro for general walk-around use
Macro for walk-around? Hm, not sure that goes together perfectly. Macro lenses are super sharp, and I think pretty much all Pentax 50mm macro lenses will give you adequate sharpness, even the ones from 1970s. Except for a couple budget or zoom macro lenses, I can't think of any that were bad. Macro prime lenses tend to all be good. But macro lenses tend to have a clinical look to them, not much character. And because they are macro, with a longer focus range, their AF will generally be slower than equivalent non-macro primes.
Anyway, I never tried it, but I heard many good things about the FA and DFA 50mm macro lenses. I've seen great photos taken with older 50mm f4 macro lenses as well, but those might need extension tubes for full macro. Also, for walk around, I would prefer an AF lens (unless it will be too dark to use AF anyway), so another reason to look at F, FA, and DFA series.
Oh, not long ago many claimed the Sigma 70mm macro is the sharpest, best Sigma lens out there. Not sure if this still holds true, as the Sigma Art series was released since, but it is still a good indication. But 70mm might be too far from 50mm. Oh, and Pentax makes a really great 35mm f2.8 macro lens, in the old SMC version and the latest HD version. Great lens, compact, for a good price.