Hi.
I was wondering whether the heads of both are interchangeable, i.e. can you screw the head of Elmar 9cm into the barrel of Wollensak Velostigmat 9cm New York? I have seen one such combo but the optical lens was destroyed so I was unable to test. I know the top of inner barrel should have matching last three digits, but I did not get to check them.
My two further questions: are Wollensak Velostigmat 9cm 4.5 lenses RF coupled? And was there ever a E. Leitz New York 9cm Elmar?
Thank you for your answers.