Archived posting to the Leica Users Group, 2002/03/16

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Subject: Re: [Leica] LTM Summaron question
From: SthRosner@aol.com
Date: Sat, 16 Mar 2002 09:07:00 EST

In a message dated 3/15/02 8:38:48 PM Eastern Standard Time, 
oliverbryk@attbi.com writes:

> Can anyone tell me the approximate production date of an Ernst Leitz Wetzlar
>  f=3.5cm Summaron 1:3.5, s/n 882556? Is there anything else of interest 
about
>  this lens?
>  Oliver Bryk

1951. If the speed isn't a problem, a very good lens optically. Dick 
Gilcreast had an interesting article on this very lens in the LHSA VIEWFINDER 
magazine, 3d quarter 2001. Dick wrote:

"The wide open f/3,5 image is quite sharp and flare-free but showing some 
positive curvature of field....[he later point out that several later 
Leitz/Leica wide-angle lenses have the same positive curvature which can even 
be a benefit when shooting in the field].....a little known design feature 
also helped to reduce [corner] falloff further: the large meniscus shaped 
rear element had the effect of enlarging the effective size of the aperture 
as the light was directed progressively toward the edges of the image, 
further improving edge and corner illumination........The typical A-36 
[f/3,5] Summaron has a flare-free performance at full aperture. It is very 
sharp over the central two thirds of the frame when shot wide open with the 
edges showing some positive field curvature.........The small aperture 
performance of the Summaron is especially noteworthy. Due to its relatively 
simple design [six elements in four groups] the lens retains a remarkable 
amount of sharpness even to the very small aperture of f/22. At this 
aperture, with the focus set at 5.5 feet, the depth of field extends from 
three feet to infinity at the center of the frame and quite a bit closer at 
the edges [because of the field curvature]."

For those who do not know Dick, he is a professional photographer of standing 
who has also a profound technical working knowledge of optics and camera 
mechanics.
His series on Legendary Leica Lenses in VIEWFINDER offers a fund of 
interesting and - to those who wish to discover for themselves the quality of 
older Leica optics - useful information.

FWIW, I have recently acquired a couple of the 1958 35/2,8 Summarons, also 
very simple design, six elements in four groups, but with Leitz-invented 
lanthanum glass 
that permitted higher levels of correction of aberrations. Both Summarons 
will still today produce outstanding imagery if you can deal with the lack of 
speed.

Seth        LaK 9
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