Computers and the Two Summicron Designs

[Marc James Small <msmall@roanoke.infi.net>]

This is picking up a thread we had 'way back when, back in the Red Dog
Saloon Era, back when Eric Welch still was signed up (hmph!).  

I came across a two-part paper written by Dr Walter Mandler, 'Leica Lenses
and Early Computers', contained in the 1989 issues 22:1 and 22:2 of the
LHSA journal, VIEWFINDER.

First, Dr Mandler confirms, as a couple of you LUG-nuts suggested, that the
first computer at Wetzlar was a Zuse Z5 installed in 1952.  Midland
installed an IBM 604 calculating punch in 1954 which was replaced in 1957
by the use of an IBM 650 in the IBM office in Toronto.  An Elliott 402F was
installed at Wetzlar in 1958 to replace the Z5 and stayed in use until
1970;  a second model went to Midland.

Mandler notes that the Zuse Z5 was used 'to redesign the Summicron 50mm f/2
for better performance at close-up distances.  The result of these
calculations was the second version of the Summicron 2/50, available both
as rigid mount and dual range lens.  (The second version has a longer
distance from the first surface to film.)"

Thus, it is confirmed:  there WAS a redesign of the Summicron between its
first (collapsible) version and the rigid/DR version, and the latter two
share the same design.

In addition to the 2/50 redesign, the Zuse was also used to design the
2.8/50 Elmar and 1.4/50 Summilux (this must be the first version of the
Summilux, as the Zuse was replaced in 1958, before the reformulation to the
current version.)

Marc


Marc James Small
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