Archived posting to the Leica Users Group, 2000/08/20

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Subject: [Leica] Back to the origin
From: "Erwin Puts" <imxputs@knoware.nl>
Date: Sun, 20 Aug 2000 12:09:18 +0200

Now that the discussion about the coating topic has reached the usual level
of rhetorical questions and proof by incidentental examples, it is time to
refocus. My objection was and still is that it makes no sense, and in fact
is incorrect,  to compare two different lenses and promoting one of both in
a more favourable light to refer to the coating technique as a single
positive criterion. Disregarding for the moment what type of coating is
applied to the Summicron-C, which is not relevant for the discussion, my
simple point is this: multi-coating in itself does not guarantee a high
level of image quality. All modern lenses are MC, but not all of them
deliver topclass imagery. And SC-lenses can deliver outstanding quality, if
the basic design is OK and if the topic of secondary reflections and flare
is incorporated into the optical and mechanical parameters. Or to expand a
bit: if the mechanical tolerances are not very tight, any theoretical
advances that MC might have, may be lost again. If the Summicron-C has SC, I
still will object to using this characteristic as a negative sales point and
find doing so incoreect from a user standpoint.
In my view, the only correct way to compare the performance of two lenses,
is testing them side by side. If then one of both is superior, you may
reflect on why this is so. According to my field and benchtests, the
Summicron-C is slightly better than the Summicron 2/35 ( 8 and 6 element
versions) and just below the Summicron 2/50 from 1969, which by some is
considered the best 2/50 ever. The Summicron-C in my view is an excellent
lens, which holds its position with the Leica M lenses of that generation
(1965 to 1975).

Erwin