<P> The history of the single - lens reflex camera (SLR) begins with the use of a reflex mirror in a camera obscura described in 1676, but it took a long time for the design to succeed for photographic cameras: the first patent was granted in 1861, and the first cameras were produced in 1884 but while elegantly simple in concept, they were very complex in practice . One by one these complexities were overcome as optical and mechanical technology advanced, and in the 1960s the SLR camera became the preferred design for many high - end camera formats . </P> <P> The advent of digital point - and - shoot cameras in 1990s through the 2010s with LCD viewfinder displays reduced the appeal of the SLR for the low end of the market . The mirrorless interchangeable - lens camera is increasingly challenging the mid price range market . But the SLR remains the camera design of choice for most professional and ambitious amateur photographers . </P> <P> The photographic single - lens reflex camera (SLR) was invented in 1861 by Thomas Sutton, a photography author and camera inventor who ran a photography related company together with Louis Désiré Blanquart - Evrard on Jersey . Only a few of his SLR's were made . The first production SLR with a brand name was Calvin Rae Smith's Monocular Duplex (USA, 1884). Other early SLR cameras were constructed for example by Louis van Neck (Belgium, 1889), Thomas Rudolphus Dallmeyer (England, 1894) and Max Steckelmann (Germany, 1896), and Graflex of the United States and Konishi in Japan produced SLR cameras as early as 1898 and 1907 respectively . These first SLRs were large format cameras . While SLR cameras were not very popular at the time, they proved useful for some work . These cameras were used at waist level; the ground glass screen was viewed directly, using a large hood to keep out extraneous light . In most cases, the mirror had to be raised manually as a separate operation before the shutter could be operated . </P> <P> Following camera technology in general, SLR cameras became available in smaller and smaller sizes; medium format SLRs soon became common; at first larger box cameras, and later "pocketable" models such as the Ihagee Vest - Pocket Exakta of 1933 . </P>

When was the single lens reflex camera invented