Lens Identification Help

[Ian Grant]

Well, your image shows it is less important for people to worry about the design type, and as Dan Fromm says - ask the lens. Which is what you have done, excellent

Ian

 

[JPD]

Very good. The previous owner put an extra marking at f:22, and maybe he found it to be the best aperture for what he was using the lens for? Probably not for portraits, though.

 

[aconbere]

Update: I popped the groups out of their holders.

I think this is another vote for rapid rectilinear /aplanat. Unfortunately there is scant information on the Schneider aplanats (rubiars?), and very few examples of aplanats as fast as 6.8.