Quote Originally Posted by PaulC View Post

I do wonder if the 516 is not mentioned in the lists is that it may never have been produced commercially, perhaps there were a handful of prototypes made before more pressing wartime jobs claimed Zeiss's attention.

Both the 516 (6x4.5) and 516/2 (6x9) were production models between 1937 and 1941.

The 516 came with a 75mm Novar 4.5 and the 516/2 with one 110m of the same kind, both on a KLIO shutter.

Production was scarce due to WWII effort, maybe because of that, not many are seen.