Four months ago I acquired a Franke & Heidecke "Heidoscop" Stereo Camera S/N 40531 in need of some TLC and it is just back after being serviced by Dave Boyle at The Camera Repair Workshop in Bletchley, Milton Keynes http://www.camerarepairworkshop.co.uk/. It was in need of CLA to the stereo compound shutter plus the focusing mechanism and the iris diaphragm mechanisms were inoperative. Additionally the mirror required resilvering and the lenses were in need of internal cleaning. The camera now works fine but I have not put a film through it yet. Some of you might not be familiar with this model so I'll outline the details below.

The knob on the side of the front is for focusing. All three lenses are coupled for focusing and they each "turn" as distinct from being on a telescopic panel. From left to right across the top of the lens panel are the aperture control ( f4.5, f6.3, f9, f12.5, f18 and f25 but without click stops), the shutter cocking lever, the time exposure and brief time control (M , Z and B) , and the shutter release including threaded cable release. The shutter speed dial is visible in the photograph below on the side of the camera. Shutter speeds are from 1 second to 1/300 second marked 1, 2, 5, 10, 25, 50, 100, and 300. Note the hinged lens caps.

Here is a close-up of the Heidoscop lens system:

Carl Zeiss Tessar (4 element) 7.5cm f4.5 taking lenses and the Carl Zeiss Suchar Triplet 7.5cm f4.2 viewing lens. The viewing lens is slightly faster than the taking lens but is only a 3 element design. The lenses are perfectly clear and clean following the service ... reflections appear to make them cloudy.

And rear view of camera with back removed showing "stereo pair" film plane and the roll film mechanism.
Most of you are probably aware that Paul Franke and Reinhold Heidecke founded the firm Franke and Heidecke in Braunschweig, Germany in 1921. Six different Franke and Heidecke stereo cameras were manufactured from 1921 until 1941 all being designed by Reinhold Heidecke. Four were designated "Heidoscop" models and used glass plates or sheet film in a magazine back. Two others were designated "Rolleidoscop" and used 'roll' film backs. This particular model is probably a Heidoscop Type 2 which has been converted for 120 roll film by use of a roll film back ... unless it is an early Rolleidoscop some of which still bore the Heidoscop logo. Unfortunately, to the best of my knowledge there are no records of actual serial numbers for each model so positive identification of model and year of manufacture is not always possible. It could have been made at any time between 1926 and 1941.
Franke and Heidecke subsequently manufactured their first "twin lens reflex" camera in 1929 and being a 'roll' film model called it the "Rolleiflex". Here is my c. 1929 "Original" f3.8 Rolleiflex S/N 106665




Note the similarities between the original F & H stereo cameras and the legendary Rolleiflex eg the viewing lens' reflex mirror box and the collapsable viewing hood ; also the "sports finder" facility in the hood.
Since 1929 the design has been cloned by many other manufacturers including Yashica, Mamiya, Ricoh and Minolta. Here is a comparison photograph showing a "modern" Yashica Mat-124G and the Original Rolleiflex. Apart from the 60 year age gap the only major differences are that the Yashica has a meter, coated lenses and a film winding crank

Hope you enjoyed reading this and viewing the photographs.
Cheers
dunk