In his summary of minor French lens makers, Corrado D'Agostini talks in his enjoyable book about Benoist & Berthiot. He writes:
"At the Universal Expo in 1900, it introduced an Aplanatic lens with 1 meter diameter and a 2 meter focus, weighing 381 kilos and cut from a piece of glass weighing 530 kilos."
His source is a L'Industrie Francaise des Instruments de Precision report from 1901.
I wonder if it actually worked -an F2 aplanat?
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