Very Large Stereo Lens Identification Question

[rossn4]

I recently got this lens and have been unable to identify it. It is a very large lens and looks like it would be for a 35mm movie camera or some sort of medium format camera. It has similarities to some of the 35mm stereo lenses like the one that fits on a Leica but this one is giant compared to that one. There is no identification on the lens. The patent number is for a Kodak focusing system so that was not helpful. The diaphragm says the lenses are f2.8 speed. If anyone knows what it is I would be grateful for any help one could provide. I have included some pictures of it with a 35mm film cartridge next to it to show its size.
#1


#2


#3


#4

[Lightshow]

What's written on the bottom left between the holes? Walch?

[DConvert]

The wide & unnecessary variation in screw types (particularly on the back)leads me to think it's a home modified lens!

For reasonable 3D effect the lenses should be further apart at least twice as far as shown in the images. But the lenses are deeply recessed in the focusing mount which may have caused severe vignetting if they were less central.

[luisalegria]

It does look a lot like the rare Kin-Dar and Hyponar lenses for the Exakta, but larger of course. And as noted, Leica and Nikon had something like this for their rangefinders.
A medium format version of the same idea?
Possibly meant for, say, a lensboard on a press camera, and it should fit on a 4x5 lensboard.

Its very nicely, professionally made, in 1940s-50s style.

Its definitely American made, with feet-only focus markings and the Kodak patent.

Its for some general-use camera because its marked from 2 ft-infinity. Its not some odd bit of lab equipment for macro/closeup work or repro.

Conversely its not from any if the common 35mm stereo cameras of the 1950s.

F/2.8 with that fairly small glass implies a fairly short focal length for medium format, not more than 50mm I think. That would make it impossible to use on any SLR, and difficult to impossible on a press camera with the usual focal plane shutters of those types. And of course it would not go into any leaf shutter.

Nice mystery there.

[Eddie46]

How often does it need feeding?

[jamaeolus]

Very strange indeed.

[Lightshow]

Can we see it partially stopped down?
I wonder if it was done as an experiment in Stereo Cine.
I also noticed the focus distance mark isn't equally between the holes, and that the twin optics would be at an angle rather than beside each other.
The slotted holes look like a modification, that they are opposite the optics, and if the optics are arranged in a stereo alignment, the focus distance indicator will be either upside down, or on the lower half, making it hard to read.

http://www.wikiwand.com/en/3D_film#/Timeline

[rossn4]

I mounted the lens on a custom made box with a ground glass on the back where it is set to infinity. The focus does work on the lens as looking through it it focuses up close corosponding to the scale as I focus it. The diaphragm works as well in one of the lenses. As a rudimentary test I took a diet coke can and focused it at approx. 2 feet from the lens and with my other hand used my camera to take a picture of the image on the ground glass. An unusual item to be sure as so far no one knows what it is. Thanks for the responses.

[luisalegria]

Good test!

What would you estimate the focal length, and do the two images together cover just a 35mm frame, or some other size?
That would more or less tell the intended format at least.

[luisalegria]

The aperture only works on one lens?

Hmm.

This may not be stereo at all.

Check out the Agfa Optima Reflex. An unusual 35mm TLR.

This isn't from one of those, but its a different angle to try.

[rossn4]

The diaphragm is working in the left side lens. The diaphragm is kind of unusual as it is two pieces that close in on each side to form a cats eye type opening. The right side either did not have a diaphragm or its just stuck and not closing down. I can't tell.

[pdccameras]

Assuming that the lens originally had two working diaphragms, perhaps this was used for making 2" x 2" passport/id photos?

[jamaeolus]

Used to make 2 images with one shot?

[ZoneV]

For me it looks like it is someting build together from a helicoid form somewhat unknown and a stereo microscope lens.
I suppose the iris ring has no function?

The lens set could likely be from a Greenough type stereo microscope / macroscope for low power enlargment. There the distance is OK for stereo vision.

https://en.wikipedia.org/wiki/Stereo_microscope