Growing fluorite crystal for lenses takes a YEAR ??
In this article http://www.the-digital-picture.com/Reviews/Canon-EF-1200mm-f... which is a review of a very rare Canon 1200mm telephoto lens. The reason I post
this is that the article tells about 'the fluorite elements aingle crystals have to grow for one year'. The lens elements are max. 20cm in diameter. I
know about the Czochralski process to grow ultrapure Si single crystals of the same diameter (20cm or more and 1-2 meters long) , so CaF2 can be grown
the same way with this process or am I wrong ?