Archived posting to the Leica Users Group, 1998/04/22

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Subject: [Leica] Re:an objective evaluation of leica M lenses
From: Dominique PELLISSIER <>
Date: Thu, 23 Apr 1998 02:21:15 +0200

I have noted over the years a certain
>>reluctance by Leitz to publish the MTF curves. I think that was in part
>>related to the company's condescension  to its users' intellectual ability
>>in undestanding optics.  It is only a recent development that some MTF
>That's not likely the case at all. First of all, one MTF chart is almost
>meaningless. Why? Because a chart only shows one test, and it takes
>hundreds of tests, different parts of the lens (center, edge, half way)
>different colors of light, different lp/mm, etc. etc. Showing one MTF chart
>is the equivalent, to me, of looking at one line of a food's nutrition
>able. Some drinks have 100 per cent of the vitamin C one needs, but not
>much else. One chart says how the lens tested out in one way. At least,
>that was Leica's argument. Let's not attribute a bad attitude to Leica that
>isn't deserved.
>Eric Welch

After having read the arguments against the mtf test of Leica lenses,
especially those developed by Erwin, I must conclude that MTF is not
objective because one test is inadequate and because a lot of measures
needs a subjective interpretation.
Well, as it is the general case in science, I must conclude that science is
inadequate or subjective.I think this great post modern discovery deserves
a  name. I propose : the LUG impossibility hypothesis.