Archived posting to the Leica Users Group, 1996/09/11

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To: leica-users@mejac.palo-alto.ca.us
Subject: Re: M3 and Wide Angle
From: imxputs@knoware.nl (Erwin Puts/imX)
Date: Wed, 11 Sep 1996 23:35:55 +0200

I did an exhaustive test comparing all 35mm for the M, including the
newest aspherical, using the Leitz optical bench and of course my own
(magazine) testwall and a series of 'normal-use' pictures (however all on
Velvia, technical Pan and tripod). My findings are as follows:
The 8 element Summicron (in comparison with the newest 7 element
Summicron)has a much lower contrast from f/2 to f4 in the center and the
corners, more flare and more astigmatism. The resolution ia also
significantly lower. The full aperture performance is absolutely no match
for the new lens. From f/5,6 both are in the same class, but the new
Summicron has a slight advantage, due to the better MTF values. There is
therefor not a marginal reduction in quality but a significant leap
forward.
The Summilux is very flare prone at full aperture and is generally speaking
only really useable for critical work (more than 12 times enlargment) from
f/2.8 on. It is one of the Leica lenses that are easily outclassed by the
competion.
The Summilux ASPH is absolutely topclass. Its full aperture performance
gives you really a punch in the eye.
The same story goes for the Summicron 50 mm (newest version) againt the 7
element (classical) Summicron. The new one is far ahead in all optical
disciplines.The original Summicron was and is a good lens certainly from
f/4, but wide open it is a low contrast lens, good in the center but weak
in the corners.
I asked the head of the optical department a few months ago why Leica
continues its drive for optical perfection when the optical performance of
the older generations already is sky high (or so the story goes). Well his
answer quite frankly is that the older generations of Leica lenses are not
so well corrected as many people assume. There is certainly room for
improvement (and if you can reduce costs while improving the optical
quality there is one clear winner: the Leica customer).