Atwin-lens reflex camera(TLR) is a type ofcamerawith two objectivelensesof the samefocal length. One of the lenses is the photographic objective or "taking lens" (the lens that takes the picture), while the other is used for theviewfindersystem, which is usually viewed from above at waist level.
In addition to the objective, the viewfinder consists of a 45-degreemirror(the reason for the wordreflexin 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 are fixed-focus models. Most TLRs use leaf shutters with shutter speeds up to 1/500th sec with a B setting.
For practical purposes, all TLRs are film cameras, most often using120 film, although there are many examples which used 620 film, 127 film, and 35 mm film. No general-purpose digital TLR cameras exist, since the heyday of TLR cameras ended long before the era ofdigitalcameras. In 2015,MiNT Camerareleased Instantflex TL70, a twin-lens reflex camera that usesFuji instax mini film.