The 'Heidoscop is a stereo camera with a reflex viewfinder, for plates or film packs (or a roll film back can be used). It was the first camera made by Franke and Heidecke (later Rollei-Werke Franke & Heidecke). The camera was made in two sizes: the first takes 45×107 mm plates, and was made from 1921-34. This was followed in 1925 by a model for 6×13 cm plates or film; this model was made until 1940. The exact specification was changed during production.
Either camera has a pair of f/4.5 Tessar taking lenses (5.5 cm focal length for the first model, and 7.5 cm for the second), mounted in a stereo Compound (later Compur) shutter and a viewing lens centrally between these. This is also a Tessar in some cameras, and a 'Sucher-Triplet' (also by Zeiss) in others.
On the top of the camera body there is a collapsible hood over the viewing screen. This would even then be a familiar feature of reflex cameras. It has a hinged plate with a focusing loupe, which can be swung over the hood.
Only a few years after the Heidoscop, in 1926, very similar cameras but with a built-in roll-film chamber were introduced alongside it, in both sizes. This was named the 'Rolleidoscop, although McKeown states that the earliest of them were sold with the name Heidoscop.
- McKeown, James M. and Joan C. McKeown's Price Guide to Antique and Classic Cameras, 12th Edition, 2005-2006. USA, Centennial Photo Service, 2004. ISBN 0-931838-40-1 (hardcover). ISBN 0-931838-41-X (softcover). p850.