Originally Posted by
Mark Sampson
The Dagor lens design was in production for about 90 years, by numerous manufacturers, not just the various Goerz companies. So their story is long and complicated; probably no one knows all the variations.
(pure opinion) The ones that seem to be the most valuable, these days, are the 1960s "Gold Dot" and "Golden" versions made by the Goerz American Optical Co., and the later 1970s-80s versions made by Schneider (although manufactured by Kern in Switzerland).
When I first asked about Dagors at the (sadly-departed) NYC store Lens & Repro, in the late '80s, I was told "they're cult lenses, collector's items; they're all going to Japan". Perhaps they were right. What it meant, at least that on that day, was that they didn't have a used 8-1/2" Dagor in stock. As it happened, I never did buy one.