Rolleiflex 3,5 Automat X (K4 50)

Rolleiflex 3.5 K4/50, also known as the Rolleiflex Automat X, is a medium-format twin-lens reflex camera for 120 film produced between 1949 and 1951, designed to create square 6 × 6 cm images. The K4/50 model was offered with several 75mm f/3.5 taking lenses, including the Carl Zeiss Jena Tessar, Zeiss Opton Tessar, and Schneider Xenar, paired with a 75mm f/2.8 Heidoscop Anastigmat viewing lens. Focusing is fully manual and uses the classic Rolleiflex TLR system, with composition and focusing performed on a ground-glass screen through the folding waist-level finder, updated on this version with a larger magnifier and provision for format masks. The Compur Rapid leaf shutter provides speeds from 1 second to 1/500 s, plus B and T settings, with X flash synchronization. Film advance and shutter cocking are operated through the side crank, while the Rolleiflex Automat system simplifies film loading and frame positioning without requiring manual alignment to the first exposure. The camera is fully mechanical and does not require batteries for operation. From serial number 1,117,000 onward, the pressure plate was also prepared for use with the Rolleikin II accessory. The Rolleiflex 3.5 K4/50 therefore combines the classic 6 × 6 format, waist-level finder, and fully manual operation typical of post-war Rolleiflex TLR cameras.