Introduced in 1983, the Bronica GS-1 in 6x7 cm format was the largest SLR produced by the company. The camera was designed to be as compact and light as possible, and weighs less than some of the smaller format Bronicas. A lens- or leaf-shutter camera, the GS-1 will synchronize flash at all available shutter speeds. It is a completely modular camera, with several optional focusing prisms and viewfinders (with and without exposure metering), lenses, and film backs. Lenses are designated 'PG', with available focal lengths of 50, 65, 100, 110, 150, 200, 250, 500 mm, and two teleconverters (1.4× and 2×).
With the appropriate back, the camera will shoot a wide range of film sizes, including 6×4.5, 6×6, 6×7 cm, and Polaroid. The 6×6 and 6×7 cm formats could be obtained in either 120 or 220 roll length. The GS-1 was also available with a dedicated G-1 speedlight flash and manually operated speed grip.