Leitz Elmar 5cm f:3.5 , Optical Glass CHANGE during 30s, after Morey 1939 patent, during war and late 40s ?

[Mustafa Umut Sarac]

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Kodak Engineer George Washington Morey published lanthanide and thorium glass patent at 1939. It was very important patent but I am not sure Germans predate it.

I want to know how many times Elmar 5 cm , f:3.5 Optical Glasses have been changed at 1930s , after 1939 Kodak Patent and during War and late 40s ?

Edited May 5, 2022 by Mustafa Umut Sarac

[romanus53]

maybe you'll find some answers here http://www.marcocavina.com/articoli_fotografici/50mm_Leica_a_telemetro/00_pag.htm

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[Anbaric]

My impression was that the Elmar never contained thorium, and elements containing lanthanum were not used until the f/2.8 version (first made in the 1950s).

https://www.lhsa.org/blog/2018/09/rare-earth-glass-leica-lenses-a-quick-and-quirky-overview

Edited May 5, 2022 by Anbaric

[Mustafa Umut Sarac]

9 hours ago, romanus53 said:

maybe you'll find some answers here http://www.marcocavina.com/articoli_fotografici/50mm_Leica_a_telemetro/00_pag.htm

Google translated the page , there was no mention of optical glass change between 1931 to after ww2. All I wanted to knew was william henry jackson elmar and mine 1938 elmar similarity. I think answer is positive. After war , coatings been applied and I think mine have no coating AFAIK.

Lanthanum comes to effect at 50s as Anbaric reports.

II want to thank both of you.