Rolleiflex, twin-lens reflex roll-film camera introduced by the German firm Franke & Heidecke in 1928. It had two lenses of identical focal length—one transmitting the image to the film and the other functioning as a viewfinder and part of the focusing mechanism. Twelve exposures, 6 cm square each, could be made on a roll of 120-size film.
The camera’s durability, precision, and compactness made it extremely popular with both amateur and professional photographers until the development of the versatile 35-millimetre single-lens reflex camera systems.