Quote Originally Posted by Xmas View Post
http://en.m.wikipedia.org/wiki/Double-Gauss_lens
the Zeiss works lost their documentation when Dresden was torched so the Russians had no more design information than Canon had for their 5cm f/1.8 LTM
the post 1982 lenses will have been derived from Mandlers type IV Summicron
There's also the Mir 37/2.8, a Flektogon design and reputed to be very good. From what I've seen on the web, it is.
One reason I've acquired a couple screwmount bodies is to play a bit with these lenses which I've been curious about for a while now.