[Leica] Zeiss Sonnar Versions

[msmall at aya.yale.edu (Marc James Small)]

At 09:52 AM 6/25/05 -0700, B Entus wrote:
>What versions are there of the Contax (classic range finder) Sonnar 
>f/1,5 5cm/50mm lens?
>
>What visual cues (in particular serial number and other engravings) 
>that allow simple identification of the version?
>
>Are there any guides available on-line?

There are quite a range of variations in the Contax RF version of this
lens, but only three optical formul?:

The initial version was designed by Bertele, arguably the finest optical
designer of the past century.  This is the version which was produced by
the Carl Zeiss Jena works during and immediately after the War in LTM,
incidentally, and which was later adopted by the Soviets for production in
both Contax RF BM and in LTM as the "Jupiter-3".  The original announcemnt
of this lens included a picture of Bertele sitting on a three-foot (90cm)
tall stack of paper claiming that this was the work which went into the
development of the design -- and the advertising campaign which followed
concentrated on the theme of Goethe's last words, "Mehr Lecht!" (more
light).  

A slight modification of this was made by the Carl Zeiss Jena works for
their Postwar production.  This was never produced in LTM to my fairly
certain knowledge.

The West German progeny of Zeiss, the Zeiss-Opton and Carl Zeiss works at
Oberkochen, did a fairly significant reworking of the lens for their
Postwar lens for the Contax IIa and IIIa.  This variant was modified on one
occasion, by the company engineers, to LTM for a Leitz executive.

These changes seem to have been made more for production convenience than
for optical performance.  I have no doubt that a 1952 Zeiss-Opton lens will
edge out a 1993 Jupiter-3 in optical performance but the difference will
probably be marginal and will almost certainly not be observeable in normal
use by me and thee.

Changes in mounting are a different matter, and there are a slew of these,
though they are unimportant to me -- my co-author, Charlie Barringer, notes
things such as minor changes in the markings on the aperture ears and the
like, but I rarely note such things (proving, I guess, that I am not a
"real" collector).  It is significant to note the following:

The very early versions of the 1.5/5cm Sonnar only closed to f/8, due to
diffraction effects.

The first coated lenses (I own one of these) closed to f/11.  Gradually,
this went through f/16 to f/22, as coating qualities improved.  By 1944,
all production closed to f/22, and this was carried over to all Soviet
production to my knowledge, though I probably should look this up:  I would
not be astonished to learn of an early ZK lens which only closed to f/16.

For Contax use, the best of the breed is a Carl Zeiss 1.5/50 Sonnar.  For
LTM use, a late Jupiter-3 (one of the black paint versions) would be
preferrable, though my late Wartime CZJ Sonnar T works quite well.

This issue is quite complex and we are only know obtaining access to the
records which make this sort of discussion feasible.  I wrote my LTM lens
book and the relevant portions of the ZEISS COMPENDIUM in a welter of
darkness:  I did not recognize this at the time but the work of folks such
as Thiele and Prochnow have expanded our horizons dramatically.

Further discussion is welcome, but be advised that I shall be out of the
loop for the next ten-day, as I am off to Anchorage, AK, to view my
grandson for the first time, and I am far too young a lad to be a 
grandfather!

Marc


msmall@aya.yale.edu 
Cha robh b?s fir gun ghr?s fir!

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