Canon's mirrorless full-frame lens mount with 54mm diameter and short flange distance, enabling compact, fast lenses.
Technical Details
The RF Mount features a 54mm bayonet diameter with a flange focal distance of only 20mm – significantly shorter than the 44mm of the EF Mount. The 12 electrical contacts transmit data at up to 10 times the speed of the predecessor system. Many RF lenses integrate a Control Ring for manual parameter control directly on the lens. The system supports lens- and body-side Image Stabilization (IS) with up to 8 stops of correction when both systems work in coordination.
History & Development
Canon introduced the RF Mount in September 2018 along with the EOS R, the manufacturer's first mirrorless full-frame camera. Four RF lenses were released simultaneously, including the RF 28-70mm f/2L USM with a constant f/2 aperture. In 2019, the EOS RP followed as a more compact variant, and in 2020, the professional models EOS R5 and R6. The system expanded in 2021 with cinema cameras like the EOS C70, bringing the RF Mount into the professional film sector.
Practical Use in Film
RF Mount cameras are used in productions such as the Netflix series "The Crown" (Season 5) and documentaries by National Geographic. The EOS R5 enables internal 8K RAW recording, while the C70 offers ProRes recording. The fast autofocus with Dual Pixel CMOS AF II and Eye Detection AF works precisely even with f/1.2 lenses. RF lenses like the 70-200mm f/2.8 L IS USM weigh 30% less than their EF counterparts with improved image quality.
Comparison & Alternatives
The RF Mount directly competes with Sony's E-Mount (46.1mm diameter, 18mm flange focal distance) and Nikon's Z-Mount (55mm diameter, 16mm flange focal distance). Compared to the EF Mount, the shorter flange focal distance allows for faster wide-angle lenses without complex retrofocus designs. EF lenses can be used via adapters without loss of quality. For existing Canon users, the RF Mount offers continuity, while new buyers can choose between the mature EF lens selection and state-of-the-art RF technology.
Current News
The Canon Cinema EOS C810 demonstrates the growing importance of the RF Mount in the professional cinema sector. The new 6K Super 35mm camera utilizes the RF Mount for maximum lens flexibility in mixed camera teams. With 4K 120fps RAW recording and improved Dual Pixel autofocus down to -7EV, the RF system is increasingly proving to be a serious alternative to established cinema mounts.