Praktica FX 1952-54 Hummel Nr. 125 Kadlubek Nr. KWE1520 Meyer-Optik Primoplan 58mm f/1.9 Zeiss Jena Pentaprism for the FX. A very brief history to recap first. The Dresden company KW began before WWII and produced what is arguably one of the first five 35mm SLR cameras. Some people believe that it was the second such camera after the much more expensive Exakta Kine cameras of 1936. The first camera in this family, first sold to the public in 1939 or so, was the M40 mount Praktiflex. Many, of whom I am one, believe that this was the first 35mm single lens reflex with an "instant return mirror". (see some arguments at http://www.photo.net/classic-cameras-forum/00Lver ) After Soviet troops occupied Dresden, the KW works was very quickly put back into production making essentially the same camera as the pre-war Praktiflex. As it turns out, these mostly went to the USSR as a part of German war reparations. Unlike the Zeiss 35mm Contax production line, everything and the personnel were kept in Dresden. The later Praktiflex had the instant mirror feature removed, and that camera evolved directly into the first Praktica - now with the Contax S, M42 mount. The FX was a refinement and was much more carefully crafted, perhaps because they were no longer sending all of their production to the Soviet Union. Here are some variants on the Praktica FX. The one labeled "Praktiflex" is only a rebranding, perhaps because of conflicting trademark holders in the USA, but is otherwise the same camera. As in the example in the picture, however, it and the other FXs were often sold with West German lenses made in the East German M42 mount (later also adopted by Asahi Pentax).