ratio. How large is the image in the frame? Most macro
aficionados prefer a lens that goes to 1:1. “1:1” means that the
image in the sensor and the subject image are the same size. Not
too many good macro lenses get to 1:1. In fact there are whole
businesses that help you get from smaller ratios (like 1:2) to 1:1
image size.
There are not all that many lenses that will give you the 1:1 ratio
and my view of putting close-up diopters on the front of my lenses
or extension tubes on the rear of my lenses (or both) is not
flattering. I have all the key diopters, tubes, etc., but I use them
only as a very last resort. Actually I hardly ever use them at all. I
know that many photographers love them but I feel a lens just as it
is sold is a perfectly balanced thing and anything added to it (front
or behind) can only lead to a degraded image. This is a fact.
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 can use lenses that are not ultra-
close.
APO (Apochromatic)
Not absolutely required (except by me), but very helpful are lenses
that are APO enabled. Apochromatic lenses are corrected for
chromatic and spherical aberration more than the common
achromat lenses. There are not many good ones, the most well-
known in the Nikon format being the Cosina/Voigtlander 125mm
APO-Lanthar, , the Leica 100mm APO Elmarit, and the Coastal
Optics 60mm APO. Recently added are two new APO lenses from
Zeiss, the 55mm Otus f/1.4 and the 135mm F/2. These are the best
lenses I have ever used. I prefer APO lenses in my work most of the
time. IMO the differences in 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.
If you are shooting insects or live-whatever, some lenses
require you to be so close to the subject that the end of the lens
actually blocks the light or the close proximity of the lens scares