Archived posting to the Leica Users Group, 1997/11/27

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Subject: Re: Russian 20mm lens for Leica
From: Marc James Small <msmall@roanoke.infi.net>
Date: Thu, 27 Nov 1997 16:28:32 -0500

At 08:01 PM 11/27/97 -0000, Russell Fox wrote:
>Various Russian wide-angle lenses are being advertised for sale in the
>U.K.  I've seen a new 20mm f 5.6 for sale, priced at around 240 pounds
sterling,
>which includes a finder & screw to M mount converter. Has anyone
experience with these >lenses?

Oh, gee, sure, guys, let's jump right onto those controversial subjects!

A few of us have the 5.6/20 Russar MR-2 lenses and love them.  A few have
tried them, and hate them.  These lenses are Topogon clones -- that is,
their formula is based on the famous Carl Zeiss Jena Topogon design, a
rather simple rectilinear wide-angle lens first designed for aerial
photogrammetric use and later adapted for use on the Contax RF, first as an
uncoated 4.5/2.5cm lens and, after the war, as a coated 4/2.5cm.

The Topogon is not a design which allows "fast" formulae, thus the f/5.6
aperture of the Russar.  It also is a bit subject to vignetting and edge
drop-off -- that is, the edges of the shot are generally darker by a stop
or two than is the center 2/3.  But the design is sharp and rectilinear --
that is, a line drawn through the FOV will be as straight as it is in real
life.

The 2.8/21 Elmarit is not one of Leitz' happier designs, which is why it is
not uncommon to find Contax and Contarex 4.5/21 Biogons converted to Leica
TM or BM:  now, the Biogon is the lens to get for the outer limit in
wide-angle performance.  

One caveat:  the Russars do vary a bit, as Soviet and Post-Soviet quality
control and quality assurance aren't what we are accustomed to and, in any
event, the Topogon design is such that these lenses are certainly
hand-assembled (the center element is paper-thin).  I would suggest you buy
with a MBG and be willing to reject one sample if you aren't satisfied --
you may have to try two or three to find one you are happy with.

I love my Russar and use it quite a bit.  And, yes, it DOES meter with the M6.

Marc



msmall@roanoke.infi.net  FAX:  +540/343-7315
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