Archived posting to the Leica Users Group, 2000/08/19

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Subject: Vs: [Leica] History of coating - Summilux 35?
From: "Raimo Korhonen" <raimo.korhonen@pp2.inet.fi>
Date: Sat, 19 Aug 2000 18:57:00 +0200

Interesting - but if Leitz knew everything about coatings, even multiple layers, in 1946 - why their coatings were so bad after WW II?
And as I stated earlier, Osterloh´s position as PR chief does not increase his credibility - but he was a Leica employee, of course.
But is my Summilux 35 from 1976 multicoated or not?
All the best!
Raimo
photos at http://personal.inet.fi/private/raimo.korhonen

- -----Alkuperäinen viesti-----
Lähettäjä: Erwin Puts <imxputs@knoware.nl>
Vastaanottaja: L U G <leica-users@mejac.palo-alto.ca.us>


<snip>
>In a report from the Naval Research Laboratory from October 3, 1946, a
>number of scientists report on the state of the coating technique in the
>Zeiss and Leitz factories in wartime. They note specifically that both
>companies use multiple layer coating as a technique, but because of its
>costly procedure, only experimentally. It can thus be established that the
>technique multilayer coating did exist at Zeiss and Leitz.
>In a report of the BJP from Otober 24, 1975, also referenced in The Leica
>Collectors Checklist, it is stated that Leitz used multiple layer coating in
>the Summilux 1.4/35 (British Patent Literature from 1957). Reports in the
>Journal of Optical Society of America in 1957 discuss the use of multilayer
>coating based on progress in the leading optical firms
<snip>
>Given Osterloh's position his statement reflects the status-quo about the
>S-C: without direct access to the company info (which is not disclosed or at
>least may not be publicized) we cannot infer from the designation that the
>S-C is coated , that is it therefore not multi-coated. This would be a fatal
>flaw in any logical reasoning.
>Erwin
>
>