nikon's 'f' model, introduced in april 1959 as the world's first system camera (if the commercially unsuccessful praktina is not considered), became enormously successful and was the camera design that demonstrated the superiority of the slr and of the japanese camera manufacturers. this camera was the first slr system that was adopted and used seriously by the general population of professional photographers, especially by those photographers covering the vietnam war, and those news photographers utilizing motor-driven nikon f's with 250-exposure backs to record the various launches of the space capsules in the mercury, gemini and apollo space programs, both in the 1960s. after the introduction of the nikon f, the more expensive rangefinder cameras (those with focal plane shutters) became less attractive.