Voigtlander Apo-Skopar w/ aperture ring AND waterhouse stops??

[Jeroen]

I'm about to buy a Voigtlander Apo-Skopar 600mm, it has an aperture ring AND waterhouse stops. On one side of the ring F-stops are engraved, on the other side numbers 10, 20, 30,... 60. Serial nr is 5075xxx so it should be from 1960. The seller doesn't know anything, does anyone here have any relevant information?

Images: https://www.dropbox.com/s/0n86vw7w7uqiwng/s-l1600.jpg?dl=0
and https://www.dropbox.com/s/0koz93wppn25pd4/s-l1600c.jpg?dl=0

[Dan Fromm]

All this is perfectly normal for process lenses such as the Apo Skopar. Waterhouse stops with circular holes act as stops, as does the diaphragm. Those with square or diamond shaped holes shape dots for photogravure. The numbers 10, 20, ... are used to orient them.

The Apo-Skopar is heliar type like the Boyer Apo-Saphir. Apo-Skopars' cemented elements are prone to separations. If you can, check for this before buying.

[Jeroen]

Thanks Dan, that helps. And I'll check for separation.