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History of CaF2 based ED glass?

Started by jonisaacs, 04/03/2018 04:42PM
Posted 04/03/2018 04:42PM Opening Post
I have been wondering when the first CaF2 based ED glasses were introduced. I have read in Thomas Back's history of A-P lens that the first FPL based A-P objectives were introduced in 1989.

Were CaF2 based glasses available before that?

Apparently some of the Japanese companies like Nikon and Pentax were producing apochromats in the early 1980's that did not use Fluorite, what did they use?

I'm hoping Roland will chime in here..

Thanks

Jon Isaacs

Posted 04/03/2018 06:31PM #1
Jon,
I found some info here that may help to some extent:
http://rohr.aiax.de/chapter%204a.htm