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Re: [Rollei] What did you do in the war? (long)



- ----- Original Message ----- 
From: "Roger M. Wiser" <wiserr  >
To: <rollei  
Sent: Monday, May 19, 2003 4:28 PM
Subject: Re: [Rollei] What did you do in the war? (long)


> During WWII the US claimed have developed optics due to
the inavailabity of
> Zeiss lens ... like Wollensak!???
>
> Roger
>
  Mixed up story and wrong war. The development of optical
glass in the United States began in 1912 with an
experimental plant set up by Bausch & Lomb. This became very
important after the outbreak of the war because supplies of
optical glass from Germany, France, and England were
completely cut off. A board of experts was assembled to
create an optical glass industry in the US. Because of their
experience, B&L was able to get into production almost right
away but other companies, especially those who were making
window glass, had a hard time of it. While window glass and
optical glass are related they are not the same, and the
criteria for them is quite different. However, by the end of
the war many tons of good quality optical glass were being
manufactured in this country by several companies.
  By the beginning of WW-2 the US was independant of Germany
for optical glass. It was made in large amounts by Bausch &
Lomb, Eastman Kodak, Pittsburgh Plate Glass Company, The
Corning Glass Works, and some others.
  Kodak in particular undertook the commercial development
of the rare earth glasses discovered at the National Bureau
of Standards. These glasses, which included the Lanthanum
and Thorium types, had the advantage of very high indeces of
refraction with relatively low dispersion.
  B&L and Kodak continued to make optical glass until maybe
twenty years ago when it became unprofitable for them. Most
optical glass is now made in Germany and Japan although
there are other sources.
  Wollensak never made optical glass. I don't know what
source they used but probably B&L and Kodak.
  I am of two minds about Wollensak. They were certainly
capable of making excellent lenses but also made some
absolute dogs which seem to me to have design rather than
manufacturing problems.
  Their shutters are excellent.
- ---
Richard Knoppow
Los Angeles, CA, USA
dickburk  

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