Adapter guide
Contax/Yashica lenses on Canon RF
Yes, this works. Contax/Yashica has a 45.5mm flange distance and Canon RF mount has 20mm, so a 25.5mm mechanical adapter with no glass fills the gap and infinity focus is preserved. Focus and aperture stay manual.
- Contax/Yashica flange
- 45.5 mm
- Canon RF flange
- 20 mm
- Adapter thickness
- 25.5 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. C/Y lenses sit at the set aperture when off the body, so the ring works directly on an adapter.
Contax/Yashica 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 |
|---|---|---|---|---|---|---|
| Carl Zeiss Distagon T* 28mm f/2.8 (C/Y) | 28mm | f/2.8 | 28mm | 45mm | 1975-2005 | $180 to $550 |
| Carl Zeiss Planar T* 50mm f/1.4 (C/Y) | 50mm | f/1.4 | 50mm | 80mm | 1975-2005 | $120 to $420 |
| Carl Zeiss Planar T* 85mm f/1.4 (C/Y) | 85mm | f/1.4 | 85mm | 136mm | 1975-2005 | $500 to $1,400 |
Frequently asked
Do Contax/Yashica lenses work on Canon RF cameras?
Yes. A plain Contax/Yashica to Canon RF adapter works with no optics. Contax/Yashica has a 45.5mm register and Canon RF mount has a 20mm register, so the adapter is a 25.5mm tube that puts the lens exactly where a Contax/Yashica body would. Plain adapter ring, no mechanism required. Zeiss and Yashica ML lenses share the mount and use the same adapter.
Do Contax/Yashica lenses focus to infinity on Canon RF?
Yes. Because the adapter restores the native 45.5mm 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 Contax/Yashica lens become on Canon RF?
On full frame Canon RF bodies (EOS R, RP, R3, R5, R6, R8) the focal length is unchanged: a 28mm lens frames as a 28mm. On APS-C (1.6x) Canon RF bodies (EOS R7, R10, R50, R100) a 28mm lens frames like a 45mm lens on full frame; the aperture and depth of field at a given distance do not change.
More on this mount: Contax/Yashica mount reference