Originally Posted by Vanishing Point Ent.
The Schneider Xenar has never been 3 elements their triplet was the Trinar, the Zeiss Jena version was the Triotar and was fitted to early Rolei's.
The Tessar has neveer been a symmetrical design, and while the Xenar was Schneider's copy of it so four elements in 3 groups (2 singles and a double) they did also make a faster f2.8 5 element version the S-Xenar in the 1930's.
By 1945 there was a shortage of specialist optical glasses used for making lenses in Germany particularly the Russian sector and there were quality issues with lenses supplied by CZJ to Rollei. This culminated in Rollei using Opton Tessar's from the new West German Zeiss company some of these may well ahve been still made in Jena but had to pass tighter quality controls.
Originally Posted by mudman
So I wouldn't be concerned your camera has a Xenar
I use a 1950's CZJ T coated f4.5 150mm Tessar and stopped down it's an excellent lens equally as good as the 1960's f4.7 150mm Xenar I used to have or the f5.6 150mm Xenar I use now which came from the last batch produced just over 10 years ago.
The only comment I would make is that some early coated lens tend to have a very cold bluish look which makes no differance for B&W but causes a slight color cast with transparency films and requires a warm up filter.