A
twin-lens reflex camera (
TLR) is a type of
camera with two objective
lenses of the same
focal length. One of the lenses is the photographic objective (the lens that takes the picture), while the other is used for the waist-level
viewfinder system. 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 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 using 120 film, although there are many examples which used other formats. No general-user digital TLRs exist, since their heyday ended prior to the digital era. The main specialist/collector-oriented exception is the Rollei Mini-Digi, introduced as a rather expensive "toy" in 2004
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