Luckily for a lot of my work I don’t always need to have a 1:1
reproduction ratio. I shoot a lot of close-up work, what I call mini
landscapes or dioramas and therefore can use lenses that are not
ultra-close.
APO (Apochromatic) Lenses
Not absolutely required but very helpful are lenses that are APO
corrected. Apochromatic lenses are corrected for chromatic and
spherical aberration more than the common achromatic lenses.
There are not many good APO lenses, the most well-known in the
Nikon format being the Cosina/Voigtlander 125mm APO-Lanthar,
the Leica 100mm APO Elmarit, the Coastal Optics 60mm APO,
and the two new Zeiss APOs, the 55mm and the 135mm. There is
a relationship between sharpness in a lens and the absence of
distortion, so I prefer APO lenses in my work most of the time. IMO
the differences in subtle coloring can be dramatic.
Minimum Focus Distance
Most lenses used for macro work have a very short minimum
focus distance. In fact many can appear too short if working with
live critters, like 50-60mm lenses.