Leica Optical Glass (was: UV or ... )

[tanovic@gol.com (Adrian Tanovic)]

On the subject of glass for Leica lenses, Appendix I of Jonathan Eastland's
"Compendium Handbook of the Leica M System" [Hove Books 1994], states the
following:

        "There has been much confusion as to whether Leitz made their own
optical glass for their production lenses.  In a letter from Leica GmbH to
the author [Eastland], dated 27 April 1993, a company executive states that
neither Leica or Leitz ever smelt its own glass from raw materials for
production purposes.  The letter acknowleges the existence of the
'scientific laboratory' for the exploration of new optical glasses, and
details the fact that 'some of the very special optical glasses were smelt
there'.  
        "This information was supplied after persistent requests by the
author over a period of two years for the company to clarify certain aspects
of claims made in advertising literature produced by the company.  In
particular, of the document entitled Leica Lenses for Optical Excellence,
List Nr. 110-190 published and printed IV/85.  On page 14 of this above
document the text states, 'Optical glass of the highest quality...is the
principle raw material, and some ten tonnes per year are produced in our own
factory, from formulations originated by the Leitz Glass Research Laboratory.'
        "Similar statements are made in other documents published by the
company, and in virtually all literature produced by the company which deals
with lens products the intimation is the same: that glass blanks are derived
from raw glass blocks and sheets produced on the premises.  Logistically,
the production requirements, even for Leica's relatively small output
(compared to Japanese manufacturers) would require extensive smelting
facilities which Leica GmbH do not have and Leitz before never had.
        "The work of the Leitz Glass Research Laboratory has, however, been
very significant.  Over 40,000 smelts (a figure consistent with the total of
ten tonnes a year mentioned in the above) have been recorded in this
laboratory before it was disposed of, and from this vast array of research,
Leitz scientists have been able to establish the exact optical glass
compositions required for the company's purposes.  But as they had done from
the beginning, Leitz procured their glass for production, in block and blank
form, from outside suppliers who were able to smelt to Leitz's highly
specialized requirements."


Adrian Tanovic
GRFP Tokyo

Replied: 15 Feb 96 22:42