The Canonflex, Canon’s first 35mm SLR camera, was introduced in 1959. With several technical innovations including the pentaprism, the quick return mirror, and the automatic aperture control mechanism, it was a practical 35mm SLR camera for all types of interchangeable lenses. Following the Canonflex, the R2000 with a top shutter speed of 1/2000 second, the fastest ever for any camera, was introduced in 1960. The R2000 evolved into the RM, which was released in 1962 and had a built-in exposure meter for the first time.
The Canonflex lens mount used a system called the breach lock mount, replacing the conventional screw system. Since the breach lock mount method prevented mount wear caused by the direct rubbing between the camera body and the lens, the optical accuracy of the camera increased. Though the breech lock mount itself remained unchanged until the introduction of the EOS system, the actuating levers of the Canomatic or R-series lenses operate differently from their FL and FD descendants.
The R-series lens were equipped with a fully automated aperture control system called Super Canomatic. This aperture control mechanism coupled to the main camera body played an important role and accelerated the development of the FL and FD-series lens. Canomatic and R-series lenses used semi-automatic or manual diaphragms.
Canon R lenses were held in the highest esteem by professional and discerning amateur photographers the world over for their unsurpassed excellence, unique optical design and precision engineering. Each lens produced the highest resolution, contrast, brilliance, and color fidelity. They were Spectra coated both internally and externally to insure maximum color and tone balance, greater light transmission, and elimination of flare. Superb optical performance, coupled with reduction in weight and design refinement made these lenses famed throughout the world.