Switar; neue rechnung, neues glass macht messbar.
Ich lese Deutsch, aber kann Englisch besser schreiben. Ich hoffe das man hier so was akzeptiert-
Years ago I measured several Alpa Switars. Radioactivity differed between the early slim mount versions and the later thick mount and macro mount versions (50mm f.1,8) , even though there were no information on its being redesigned.
My guess is that there was a new calculation made and that glass types were changed. This points towards measuring ionizing radiation as a tool for dating unannounced design changes.
p.