Found article from 1969 on Canon FL-L fluorite lenses
From
RichA@21:1/5 to
All on Mon May 30 23:17:35 2022
Funny thing, they used it in relatively slow 300 and 500mm lenses then. I had one of the 300mm. After that, you'd have expected colour correction to have vastly improved in lenses thereafter, but it took DECADES for the creation of good ED glass to
work in that regard apart from Canon's use of fluorite. Fluorite still achieves the best colour correction, despite fluoro-crown glass mixes being very good today. I'm just surprised its use wasn't adopted by more camera companies, at least in fast and
medium speed long telephotos. Now, ED glass is ubiquitous in even lesser glass. Large fluorite boules have been available since the 1960s.
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