Originally posted by roscot I don't shoot many macros, but the 3 lenses that seem to get the most accolades are:
Pentax smc DFA 100mm f2.8 macro
Sigma 105mm f2.8 EX DG Macro
Tamron 90mm f2.8 Di Macro
I'm sure these are all fine. But I don't think any of them are
great lenses.
I think they all have too much purple fringing. The Pentax has way too much chromatic aberrations at wider apertures. If I were to rank them according to pleasant bokeh, it would be (1) Pentax, (2) Tamron, and (3) Sigma - although they're all (like sharpness) within a very narrow range.
When I first got the 100mm Pentax macro, I took some insect photos. I all of a sudden wished I had a longer lens, like Stephen's 180mm Sigma. (Check out his galleries - WOW.) But the longer you get, the higher shutter speeds you need, and the harder it gets to hand hold much. (You'll surely need a flash, even if you think you don't.)
Now I realize that I don't do too many insect shots and I'm leaning towards the 50mm end of the macro range. Maybe the Pentax 35mm macro will be the one.
Anyway, some others to consider are the Vivitar/Kiron/Lester A Dine 100-105mm macros and some of the older Tamron 90mm ones. I'm casually looking for an old Tamron 90mm f/2.5 macro.
Until then I'm getting decent results from my Pentax DFA 100/2.8 and my K-mount converted Nikon 55/3.5 Micro.