Small folder. Mystery purchase. Zeiss?

[yashica1943]

I have just bought from a well known auction site a small, old, folding camera with a flat back for plates or sheet film. I have done hours of research on the 'net and in McKeown's ( the whole 500+pages !) To find out the maker.

It has a Zeiss Tessar lens marked  1:4.5 f 55cm Carl Zeiss Jena Nr 542234, a Deckel shutter and the only other markings around the outside of the lens is the German DGRM, DRP patent notices. There is a tubular threaded brass accessory? about 18mm long which screws over the lens and has a rectangular mask.

The body is only 80 x 57mm at the rear made of steel. And obviously has no folding bed, but four spring loaded struts.

The rear is rather strange, inside the 57mm x 38mm cavity there is a black card which has a 'portrait' style cut out 18 x 25mm which matches the viewfinder orientation.

The thin sliding back (steel) has a hinge with a card inside with an aperture of 18 x 25mm and a frosted plastic inside with a clear circle in the centre, all fitted in with shiny black tape.

The body of the camera is finished in thick paint, probably hand painted.

I suspect that there may have been a leatherette covering at some time with, possibly a makers name embossed.

As it is there is not room for a plate inside the back and it is not light-tight.

What the make is? It looks a bit like an Ernemann or  but don't think so.The corners of the body are square, not rounded and the lens plate/mount is different.

What use it was put to? And any idea of value?

Any help would be appreciated.

[yashica1943]

I have just looked at the viewfinder on the mystery camera. It appears to be a later addition. It looks like a Zeiss viewfinder. Square but masked with tape to a portrait form. Been trying all afternoon to identify it!

Also I have been trying to cock the shutter with the little lever under the lens. I have moved the shutter speed dial, but I cannot see the speed indicated and the shutter now works at varying speeds.