Twin-lens reflex camera

A twin-lens reflex camera (TLR) is a type of camera with two lenses with the same focal length: a viewfinder lens and a taking (or objective) lens, which is usually viewed from above at waist level.

In addition to the objective, the viewfinder consists of a 45-degree mirror (the reason for the word reflex in the name), a matte focusing screen at the top of the camera, and a pop-up hood surrounding it. The two objectives are connected, so that the focus shown on the focusing screen will be exactly the same as on the film. However, many inexpensive "pseudo" TLRs (eg. the Kodak Duaflex) are fixed-focus models to save on the mechanical complexity. Most TLRs use leaf shutters with shutter speeds up to 1/500 of a second with a bulb setting.

For practical purposes, all TLRs are film cameras, most often using 120 film, although there are many examples which used 620 film, 127 film, and 35 mm film. Few general-purpose digital TLR cameras exist, since the heyday of TLR cameras ended long before the era of digital cameras, though they can be adapted with digital backs.