French madness? Here I am Thanks, Steven, for the document.
If I read well, the text in French speaks about lentilles aplanétiques which means : single lens element, or cemented doublet, not a compound lens like the Carl Zeiss Monster
What is unusual is the f/2 relative aperture of this single lens element (or doublet). I have no idea of its shape, so that is deserves the name 'aplanétique'.
Regarding big lenses, here is a wiki-list of biggest refracting telescopes still in operation, the champion is in Yerkes observatory in the US with a diameter of one meter = 40", although a bigger lesn of 1.25 meter = 50" in diameter was built in 1900 in France
http ://en.wikipedia.org/wiki/List_of_largest_optical_refracting_telescopes
The 1900 1.25 m telescope
http ://en.wikipedia.org/wiki/Great_Paris_Exhibition_Telescope_of_1900
But the f-number of those refective telescope lenses is around f/15, not f/2.
There is one refractrive telescope of diameter 80 cm, actually this is a twin-lens telescope (80 cm and 60 cm) in Meudon observatory near Paris, la grande lunette de Meudon, the Meudon 33-inch Great Refractor.
http://www.obspm.fr/histoire/meudon/meudon04.gif
This telescope was designed to make precise observations and photographs of planets. So the Meudon lens definitely deserves the name of photographic lens, although it is not a f/2.
This big telescope is currently under repair and as far as I've read, will be available for the public in the near future.
Hence optical technology of the 1900's was able to fabricate glass lenses of at least 40" in diameter, and the instrument still exists in Yerkes observatory; the record being 50" and well-documented although no longer existing.
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