Archived posting to the Leica Users Group, 1999/04/13

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Subject: [Leica] lens comparisons between brands
From: Erwin Puts <>
Date: Tue, 13 Apr 1999 20:41:39 +0200

This topic as a classical one, not only on the Lug, but in every photo
magazine and gathering of photographers. It is also a futile one IMHO.
Generally speaking the big four (C, L, N, Z) really do know how to design
quality optics. The design of an optical system in essence means balancing
aberrations that cannot be eliminated or cancelled out. These aberrations
are known to a Leica designer as well as to a Nikon designer. How a
designer  does this balancing act is partly art and partly specific know
how of the effect of residual aberrations on the image quality. The
definition of image quality differs per company/design staff. Again part of
it canbe quantified (merit function and its resultants MTF/OTF), but part
is art (a spot diagram is easily generated, but analysing this form with
respect to potential image quality is very very difficult. Leica is a
master of this art and that is why we all like their products.
An optical system is too complex to be able to use a one dimensional
evalution scale as sharpness or contrast or whatever. So any discussion
whether Nikon is sharper or not viz a viz Leica is void. Leica differs from
Canon and Nikon and Zeiss, as all the others do from each other because
every designer has a different set of priorities and weighting of the
residual aberrations.

In stead of discussing top class lenses in simple terms as better or worse,
it would be more instructive and enlightening to evaluate  lenses as having
certain optical characteristics that can support your type of imagery.
I really wish we stop this simple comparison game. If we could set up a
complete list of lens characteristics we might end with a list of 50 or
more personality traits. Let us not be so naive as to assume that any lens
from whatever manufacturer can score on all characteristics.