comparisons
comparisons
hi Michael -
Given that the M7 lenses are non-retrofocus designs along the lines of the biogon formula, they will inherently be superior to the retrofocus designs for the small-format cameras from zeiss and nikon. Even if the retrofocus 35mm lenses were better, the much larger format of the 6x7 neg would supercede any advantage of the lens, when it comes to results-on-paper.
Mamiya did publish MTF of some of their lenses. I have the MTF for several of the RZ67 lenses posted on the abovementioned site, I believe. (if not, I can post them).
Comparisons are only valid when comparing using similar techniques, so for example all of Chris Perez's comparisons are valid amongst themselves. Likewise the Pop Photo tests are valid within their subset. The most useful part of the test data is determining which apertures are best for which lens. Generally f/8-f/11 will be the sharpest on the M7 stuff.
Some of the RZ67 APO teles are sharpest wide open (!), indicating diffraction-limited performance at wide open aperture - that is about as good as lenses can get. Few lenses can match that claim, even today.
FWIW
-Ed