More important than the focal length is the magnification ability of the macro. Getting one that does 1:1 is no easy task.
The most common macro focal lengths are 50mm and 100mm (give or take a few mm). The 100mm can be situated further from the subject to achieve the same magnification than the 50mm - this may be useful for flash use, composition, etc. However, on APS-C (and smaller) bodies, the 50mm focal length may be more versatile - making a good secondary portrait lens (not all macro lenses make good portrait lenses though - some are too sharp for flattering portraits, some have too small an aperture, and some have bad/busy bokeh at portrait distances).
For me, the characteristics of a lens and its suitability for macro and other uses are more important to me than just the focal length, so I left my vote blank. If I were to choose between two equally performing lenses at 50mm and 100mm though, I'd probably go for the 50mm. The Sigma 50mm f/2 macro lens is quite well regarded, and is available in a variety of mounts. It is MF only, though, IIRC, and that can be a deal breaker for some. Canon's 50/2 macro lens is also pretty good - as a rule, the macro is/should be the sharpest lens in a manufacturer's lineup.
PS Primes only also for me. You'll usually find that "macro" zooms either aren't very "macro", or not very good (or both). The Tamron 17-50/2.8 is an excellent walkaround lens, though. But its 1:4.5 magnification is pathetic for a "macro".
Last edited by Voldenuit
on Wed Mar 31, 2010 12:29 pm, edited 1 time in total.
Wind, Sand and Stars.