Adapter guide
Canon FD lenses on Canon RF
Yes, this works. Canon FD has a 42mm flange distance and Canon RF mount has 20mm, so a 22mm mechanical adapter with no glass fills the gap and infinity focus is preserved. Focus and aperture stay manual.
- Canon FD flange
- 42 mm
- Canon RF flange
- 20 mm
- Adapter thickness
- 22 mm
- Optical elements
- None required
Setting it up
Enable Release shutter w/o lens and turn on MF peaking. Canon APS-C bodies use a 1.6x crop rather than the 1.5x of other systems.
Automatic diaphragm driven by a stop-down lever on the rear of the lens. Off the camera, the lens sits wide open until that lever is moved.
Canon FD lenses and their field of view on Canon RF
Effective focal length changes with sensor size. The lens itself does not change; the smaller sensor simply captures a narrower part of the image circle.
| Lens | Focal length | Aperture | Full frame | Frames like (APS-C (1.6x)) | Years | Used value |
|---|---|---|---|---|---|---|
| Canon FD 35mm f/2 (concave) | 35mm | f/2 | 35mm | 56mm | 1971-1979 | $150 to $500 |
| Canon FD 50mm f/1.4 S.S.C. | 50mm | f/1.4 | 50mm | 80mm | 1971-1990s | $55 to $200 |
| Canon FD 55mm f/1.2 S.S.C. | 55mm | f/1.2 | 55mm | 88mm | 1973-1979 | $180 to $600 |
| Canon FD 85mm f/1.8 S.S.C. | 85mm | f/1.8 | 85mm | 136mm | 1974-1990s | $100 to $340 |
Frequently asked
Do Canon FD lenses work on Canon RF cameras?
Yes. A plain Canon FD to Canon RF adapter works with no optics. Canon FD has a 42mm register and Canon RF mount has a 20mm register, so the adapter is a 22mm tube that puts the lens exactly where a Canon FD body would. The adapter needs a control ring (usually marked Open and Lock) that engages the stop-down lever. Mount the lens in the Open position, turn the ring to Lock, and the aperture ring then stops the lens down normally. FD lenses cannot reach infinity on any DSLR without corrective optics because 42mm is shorter than every DSLR register.
Do Canon FD lenses focus to infinity on Canon RF?
Yes. Because the adapter restores the native 42mm register, infinity focus is preserved and the full focus scale on the lens stays accurate. Adapters machined slightly short let the lens focus past infinity by a small margin, which is harmless; adapters machined long stop short of infinity, so buy from a maker with tight tolerances.
What focal length does a Canon FD lens become on Canon RF?
On full frame Canon RF bodies (EOS R, RP, R3, R5, R6, R8) the focal length is unchanged: a 35mm lens frames as a 35mm. On APS-C (1.6x) Canon RF bodies (EOS R7, R10, R50, R100) a 35mm lens frames like a 56mm lens on full frame; the aperture and depth of field at a given distance do not change.
More on this mount: Canon FD mount reference