Rectaflex (followed by Contax S) was the first SLR camera introducing the modern pentaprism eye-level finder. The first prototype (Rectaflex 947) was presented in 1947, with a final presentation in April 1948 and start of series production (A 1000) in September the same year, thus hitting the market one year before the Contax S, presented in 1949. Both were preceded by Alpa-Reflex, first presented to a wider public in April 1944 at the Swiss Trade Fair in Basel (Schweizer Mustermesse). Alpa’s production was slow up to 1945, and it lacked a pentaprism, so the image was reversed left-to-right. Zeiss Zeiss had begun work on a 35mm SLR camera in 1936 or 1937. This camera used an eye-level pentaprism, which allowed eye-level-viewing of an image oriented correctly from left to right. Waist-level finders, however, showed a reversed image, which the photographer had to mentally adjust for while composing the image by looking downward and viewing and focusing. To brighten the viewfinder image, Zeiss incorporated a fresnel lens inbetween the ground-glass screen and the pentaprism. This design principle became the conventional SLR design used today. World War II intervened, and the Zeiss SLR did not emerge as a production camera until Zeiss, in the newly created factory in East Germany, introduced the Contax S in 1949, with production ending in 1951. The Italian Rectaflex, series 1000 went into series production the year before, in September 1948, thus being market-ready one year before the Contax. Both were historic progenitors of many later SLRs that adopted this arrangement. Praktiflex Praktica In 1939, Kamerawerk Niedersedlitz Dresden presented the Praktiflex at the Leipzig spring fair. The camera was a waist type with an M40x1 screw mount and a horizontal cloth focal shutter. This camera is the pattern for most of the 35 mm SLR cameras and also for the Japanese and the digital SLR cameras today. After the war, Praktiflex was the most manufactured 35 mm SLR in Dresden, especially for the Russians as reparations. KW changed to the M42 screw mount invented at Zeiss for Contax S—later used by Pentax, Yashica and others to become a near universal mount. In 1949, it was redesigned with longer shutter speeds, and the name was changed to Praktica. In 1958, KW Niedersedlitz became a part of the VEB Kamer und Kinowerk (old Zeiss), later VEB Pentacon. Praktica was typically a consumer/amateur camera. Many developments were added. It was