An SLR is a camera that typically uses a mirror and prism system (hence "reflex" from mirror reflection) that allows the photographer to see through the lens and see exactly what is being captured.
The first SLR cameras were developed as early as the 19th century. The first 35mm SLR as we know it today was the Duflex from Hungary. Among the largest manufacturers still active today are Nikon and Canon. Other manufacturers were Mamiya, Pentax, Minolta, Cosina or Olympus. Of course, cameras were also manufactured outside of Japan. The GDR, for example, also had a large output of analog SLR cameras. VEB Pentacon, for example, produced Praktica cameras, some of which were sold in the West under the Revue and Porst trademarks.
SLR film cameras were produced for most film formats and also for digital formats. Most film-based SLR cameras use the 35mm format, as this film format offers a variety of emulsions and film speeds and good image quality.
A small number of SLRs have been produced for APS, pocket film format, and medium format film. In digital photography, especially professional, SLR cameras are still standard today.
Another commonality for many SLR cameras is the interchangeable lenses. Depending on the subject and shooting situation, the photographer thus has the option to select a suitable lens. Especially Nikon, Canon, Minolta and Mamiya offer a wide range of lenses for their cameras. There is also a large selection of lenses for the M42 thread. Here, both cameras and lenses were produced by many manufacturers.
