Please help about some rare brass lens!

[photojournalism]

Hello!
Have anyone know anything about the brass lens - Planistigmat 313mm f6.6 Phos Varsovie?
As I know the owner of Phos factory (founded 1904) was Alexander Ginsberg who was studied and had work in Carls Zeiss company. This lens seems symmetrical and convertible. If you know what kind is this lens, how much it can cost today or any other information will be useful.
Thank you, Andrey.
largeformatphoto@yandex.ru

[photojournalism]

Found some interesting information:

It appears, Alexander Ginsberg was married to Carl Zeiss daughter, that's why he had access to Zeiss lens design and patents.

[photojournalism]

P.S.
Here is the pic of this lens

[Ole]

At the moment I don't know anything about it, but I might find out something when I get home next week.

[Whiteymorange]

Vade Mecum lists some (very little) info on aplanistigmat lenses by "Fos" and says in another place that the Warsaw factory produced lenses for export from 1899 to 1915. Not much more, I'm afraid.

[desertrat]

You can get some information on how the lens is constructed by counting reflections. Close the diaphragm all the way so you can check the front and rear groups separately. That way you don't have to look through all the lens groups at once. Look at the reflections of a small light bulb in the front lens group. Bright reflections are where glass meets air. Very dim reflections are where two elements are cemented together. Count the bright and dim reflections. Then do the same with the rear lens group. Here are some examples:

Two bright reflections - single lens element
Two bright and one dim reflection - a cemented doublet
Two bright and two dim reflections - a cemented triplet
Two bright and three dim reflections - a cemented quadruplet
Four bright reflections - two single elements, air spaced
Four bright and one dim reflection - a single element, an airspace, and a cemented doublet.

There are more combinations, but this is a start. Let us know what you find.

[photojournalism]

Thank you! That'll be great!

[photojournalism]

Thank you for information.

[photojournalism]

You can get some information on how the lens is constructed by counting reflections. Close the diaphragm all the way so you can check the front and rear groups separately. That way you don't have to look through all the lens groups at once. Look at the reflections of a small light bulb in the front lens group. Bright reflections are where glass meets air. Very dim reflections are where two elements are cemented together. Count the bright and dim reflections. Then do the same with the rear lens group. Here are some examples:

Two bright reflections - single lens element
Two bright and one dim reflection - a cemented doublet
Two bright and two dim reflections - a cemented triplet
Two bright and three dim reflections - a cemented quadruplet
Four bright reflections - two single elements, air spaced
Four bright and one dim reflection - a single element, an airspace, and a cemented doublet.

There are more combinations, but this is a start. Let us know what you find.

Hello! Thank you!
It's great test, I didn't know about it!
The test shows a cemented doublet in both elements.
I analysed some information, thought a lot and decided that planistigmats were made according Carl Zeiss Double-Protar design.
What do you think?

Andrey

[Ole]

If it's a cemented doublet in each cell it's not a Doppelprotar - that takes at least three elements in each cell.