The Rolleiflex twin-lens reflex
1929
Two matched lenses, one to view and one to take, on a compact 120-film camera with square 6×6 frames. It set the standard for professional medium format for thirty years.
How it began
Franke & Heidecke in Braunschweig made stereo cameras. In 1929 they used the same idea of two lenses side by side, stacked vertically, to make a reflex camera for roll film: the Rolleiflex.
How it works
The upper lens throws its image via a mirror onto a ground glass seen from above, and the lower lens, focused in step, exposes the film. Because the viewing lens has no shutter, the image never blacks out. The square frame meant the camera never had to be turned on its side.
Why it mattered
It was smaller and quicker than plate cameras but made big, sharp negatives. Portrait, fashion and press photographers adopted it, as did street photographers such as Vivian Maier, who could look down into it without raising the camera to their eye.
Limits and what replaced it
The viewing lens sees slightly differently from the taking lens (parallax), and lenses could not usually be changed. Single-lens reflexes such as the Hasselblad took over for professional medium format.
Today
Used Rolleiflexes are still sought after, and new twin-lens reflexes are made in small numbers.