Flange focal distance of 9.5 mm camera ?

[Joel Pierre]

What can be the flange focal distance of a 20 mm Cinor lens of a 9.5 mm camera (Pathé National II) ?

 

The thread diameter of the mount is the same as the D-mount (15.88 mm), but the flange focal distance seems to be the same as the C-mount (17,526 mm).

 

Can I use a C-mount lens (with a D-mount > C-mount adapter ring) on a 9.5 mm camera ?

 

Mechanically, yes, but optically ?

 

[Zac Fettig]

I would guess not. If the FFD is the same, it'll push the focal plane out 5.23 mm in front of the film plane.

[Dom Jaeger]

Yes an adapter will just make a C mount lens focus at the D mount FFD of 12.29mm, so if you're correct about that camera I'm afraid you're stuck with the lens the camera came with. FWIW, all of the 9.5mm cameras I have are either standard C mount or have a fixed lens.

[Joel Pierre]

The camera is a Pathé National II 9,5 mm with the standard lens (a Cinor f=1.9 / 20 mm).

 

There were three lenses designed for this camera plus a Hyper-Cinor screwed at the front and dividing the focal length of the lens by two (I bought this on eBay).

 

The distance between the film plane and the lens mount is 28 mm.

 

The distance between the rear lens and the film is about 17-18 mm

 

As the size of the 9,5 mm film is between 8 mm and 16 mm, I guess the flange focal distance, too.

 

 

Edited December 28, 2012 by Joel Pierre

[Joel Pierre]

Here are the approximate dimensions that I could measure of my Cinor 1,9/20 mm lens on Pathé National II camera: