Archived posting to the Leica Users Group, 1996/04/04
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The first "glass explosion" occurred in the late 1800's when Ernst Abbe
convinced Otto Schott to dedicate his glass research to the development and
production of high-refractive index optical glasses. The second occurs in
the late 1940's when Leica developed the use of rare-earth glasses,
especially Lanthanum mixtures. As Laney wrote in his Leica Collectors Guide
(p. 123):
The decision of Leitz to set up their own glass research
laboratory after the war, probably to reduce their dependence
on Schott who naturally favoured their parent, Zeiss, was
the step that revolutionized Leitz lenses in time for the
M3. Its first major achievement was in making practical,
highly refractive glasses with low dispersion by incorporation
of lanthanum oxide in the melt... The first fruit of this
investment was spectacular -- the 50mm f/2 Summicron of 1953,
which set entirely new standards for 35mm camera lenses.
And, later (p. 132):
Summicron 50mm f/2: Clearly derived from the Summitar, but
with a superior performance brought about by new glasses giving
the designer greater freedom... Three of the elements were made
from glass developed by Leitz.
The prototype Summicron -- the prized "Star Summitar" -- dates from early 1952.
Other authorities discussing these developments include Keller and Rogliatti.
Leitz pioneered the use of computers in lens design (1949) and the use of
rare-earth glasses. The Wetzlar, and now Solms, insistence on being at the
cutting edge of technology is quite, quite impressive!
Marc
msmall@roanoke.infi.net FAX: +540/343-7315
Cha robh bas fir gun ghras fir!