More treasure hunting.

[jamaeolus]

I bought this lot for 79 USD. I can tell its a superfast normal 5* 1.2 but I don't know if its the 58mm or the 55mm. Anybody know? If so how?
photo is copied from ebay ad

[kansalliskala]

get some wine, relax and wait

[casualcollector]

Later FT. Serial number on top instead of on the back. The lens is the 55mm as it has the A-M ring at the rear of the lens instead of the 58s preset ring at the front. That A-M ring is also the difference between the 6 element and later 7 element 50/1.4 and early and late 50/1.8. Looks like a Vivitar zoom comes with it!