There often are several such points is the series and I need to be
able to see to focus in the viewfinder to do that and I want a fast
lens for visibility. For example, someone commented recently about
the Nikon 70-180 Zoom Macro. I spent a couple of years intensely
using that lens but gradually abandoned it because its widest
aperture is f/4.5. This morning I got that lens out in case I had
made a misjudgment or might see it differently today. It was about
8:30 AM here and the sun had not really gotten strong.
Looking through the 70-180mm it was very dim indeed and not at
all bright enough for my work. On a bright day the lens would be
fine but I don’t shoot in bright sunlight and even tend to avoid
bare sunlight, concentrating more in shadows or light haze. The
70-180mm Zoom Macro is a wonderful lens, but not for me for the
reasons mentioned.
Focus Throw
Something not often mentioned is the focus throw of a lens,
how many degrees does the barrel have to rotate to go from
close-up to infinity. I was surprised at some of the fine macro
lenses that have a short focus throw. For macro work and
especially for focus stacking I need a longish focus throw or
else put the camera on a focusing rail. I prefer the long focus
throw on a lens to carrying a rail around.
I was shocked to find that the very expensive Coastal Optics
60mm APO macro lens has a focus throw of only 210 degrees. For
example the CV-125 APO has a focus throw of 630 degrees and
the Leica 100mm Elmarit has one of 710 degrees. However, the
old Micro-Nikkor 60mm f/2.8 D macro has a throw of only 120
degrees and that is not desirable.
The wider the angle macro lens (50mm, 60mm, etc.) the more
important it is to have a long focus throw. Macro work is just the
opposite of sports photography where you want a short focus
throw. In macro, and most of all in focus stacking, a long focus
throw is a big advantage. You need it or use a focusing rail.
Reproduction Ratio
Another feature to keep in mind is the reproduction