Does anybody got info about this lens?
It doesn´t say Carl Zeiss anywhere buy construction is identical as a Contax I lens. Serial number is 60080 and it says R.1038
I bought in a store in Buenos Aires.
I'm looking at my 5cm F2 Sonnar, made for the Contax I. The SN for my lens is in the 1.4Million range. This is a rigid lens, no filter threads, and stops down to F22. My lens appears to have a larger front element than yours.
After WW-II, many Zeiss lenses were "cobbled together" from existing parts, many had a "one-off" appearance. Your lens looks unique.
The SN range of your lens would normally place it as a post-war, West German lens. "Zeiss Opton". The "R.1038"- maybe an X-Ray lens. I have an early 5cm F2 Sonnar made in the 1930s that was coated and mounted in a new fixture, probably used in an X-Ray type machine.