Canon · Mirrorless mount

Canon RF — flange distance, protocol, and adapter compatibility

Canon's full-frame mirrorless mount. Same 54 mm throat as EF but 20 mm flange (vs EF's 44 mm) and a 12-pin contact array supporting faster lens-to-body bandwidth. Mechanical-only EF→RF adapters are 24 mm thick, preserving every EF and EF-S lens's autofocus, IS, and aperture control with no glass.

Mount specifications

Flange focal distance: 20 mm
Throat diameter: 54 mm
Electronic protocol: Canon RF
Supported formats: full-frame, APS-C
Manufacturer: Canon
Introduced: 2018
Status: Active production

Adapting Canon RF lenses onto other bodies

You own Canon RF glass and want to mount it on a body with a different lens mount. Rows are sorted by feasibility.

Body mount	Result	Adapter examples	Caveats
Canon RF (cine) flange 20 mm	Native AF fullIS fullAp. electronic	no adapter required — stills RF glass mounts natively on Canon RF-mount cinema bodies (C70, C400, R5 C)	Cinema RF bodies preserve every stills-RF feature: Dual Pixel CMOS AF II, in-lens IS, electronic aperture and Control Ring. C70 and C400 use the standard RF mount; no special adapter is needed for RF-mount L-series stills lenses.
Canon EF-M flange 18 mm	Mechanical MFIS lens-onlyAp. wheel1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon RF lens and Canon EF-M body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Nikon Z flange 16 mm	Mechanical MFIS lens-onlyAp. wheel	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon RF lens and Nikon Z body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Sony E (incl. FE) flange 18 mm	Mechanical MFIS lens-onlyAp. wheel	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon RF lens and Sony E (incl. FE) body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Fujifilm X flange 17.7 mm	Mechanical MFIS lens-onlyAp. wheel1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon RF lens and Fujifilm X body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
C-mount flange 17.526 mm	Mechanical MFIS lens-onlyAp. wheel2.7× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon RF lens and C-mount body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Fujifilm GFX (G-mount) flange 26.7 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -6.7 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Micro Four Thirds flange 19.25 mm	Speed booster MFIS lens-onlyAp. wheel2× crop	Speed Booster / focal-reducer family	Flange clearance is only 0.8 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
L-Mount flange 20 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only 0.0 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Leica M flange 27.8 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -7.8 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.

Adapting other lenses onto a Canon RF body

You own a Canon RF body and want to mount glass from other systems. Mirrorless-lens-onto-DSLR-body combinations are omitted (rear element collides with the mirror box).

Lens mount	Result	Adapter examples	Caveats
Canon RF (cine) flange 20 mm	Native MF—Ap. electronic	no adapter required — RF-cine glass mounts natively on every RF body	RF-cine lenses are mechanically and electronically stills RF with a cine-geared barrel — they mount native on R5, R6, R3, C70, C400, R5 C, etc. Canon CN-R primes carry electronic aperture but no AF motor; iris is body-controlled, focus is fully manual via 0.8 MOD geared ring.
Canon EF flange 44 mm	Mechanical AF fullIS fullAp. electronic	Canon EF-EOS R (plain) Canon EF-EOS R with Control Ring Canon EF-EOS R Drop-In Filter (Variable ND / Circular Polarizer)	Every Canon EF lens since 1987 preserves full AF, IS, and electronic aperture. EF-S lenses auto-crop to APS-C; full-frame RF bodies switch to 1.6× crop mode.
Canon EF-S flange 44 mm	Mechanical AF fullIS fullAp. electronicvignettes	Canon EF-EOS R	Body auto-crops to APS-C (1.6×); resolution drops accordingly on full-frame RF bodies.
Nikon F flange 46.5 mm	Mechanical MFIS lens-onlyAp. wheel	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Nikon F lens and Canon RF body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Sony A / Minolta A flange 44.5 mm	Mechanical MFIS lens-onlyAp. wheel	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Sony A / Minolta A lens and Canon RF body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Fujifilm GFX (G-mount) flange 26.7 mm	Mechanical MFIS lens-onlyAp. wheel1.27× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Fujifilm GFX (G-mount) lens and Canon RF body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
M42 (Pentax / Praktica screw mount) flange 45.46 mm	Mechanical MFIS lens-onlyAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between M42 (Pentax / Praktica screw mount) lens and Canon RF body.
Leica M flange 27.8 mm	Mechanical MFIS lens-onlyAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Leica M lens and Canon RF body.
Pentax K flange 45.46 mm	Mechanical MFIS lens-onlyAp. wheel	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Pentax K lens and Canon RF body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
PL (Positive Lock) flange 52 mm	Mechanical ——Ap. ring	Wooden Camera PL-RF IBE Optics PL-to-RF Mount Module (interchangeable on C70 / C400) Vocas PL-RF	Pure mechanical — PL has no electronic interface, so AF / IS / electronic iris are all n/a. Cooke /i or ZEISS eXtended Data contacts (where present) are not currently surfaced through these RF adapters.
Canon EF (cine) flange 44 mm	Mechanical MF—Ap. electronic	Canon EF-EOS R (plain) — works for any EF-cine prime or zoom Canon EF-EOS R 0.71× Cinema Speed Booster (Super 35-to-full-frame relay, designed for Canon EF-cine on C70's S35 sensor — note: the C70 itself is S35, but full-frame R5/R5 C also accept this adapter on the EF-cine glass)	Mechanically identical to mounting any EF lens on an RF body — the 24 mm EF-EOS R adapter preserves electronic aperture and is fully transparent. AF stays manual-only because the cine lens has no AF motor; iris control is body-driven via the EF pins.
Exakta flange 44.7 mm	Mechanical MFIS lens-onlyAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Exakta lens and Canon RF body.
T-mount (T2) flange 55 mm	Mechanical MFIS lens-onlyAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between T-mount (T2) lens and Canon RF body.
Praktica B flange 44.4 mm	Mechanical MFIS lens-onlyAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Praktica B lens and Canon RF body.
Konica AR flange 40.5 mm	Mechanical MFIS lens-onlyAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Konica AR lens and Canon RF body.
Minolta SR / MC / MD flange 43.5 mm	Mechanical MFIS lens-onlyAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Minolta SR / MC / MD lens and Canon RF body.
Canon EF-M flange 18 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -2.0 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Nikon Z flange 16 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -4.0 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Sony E (incl. FE) flange 18 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -2.0 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Fujifilm X flange 17.7 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -2.3 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Micro Four Thirds flange 19.25 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -0.8 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
L-Mount flange 20 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only 0.0 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
C-mount flange 17.526 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -2.5 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.

Adapter SKU teardown

Curated adapter SKUs that involve the Canon RF mount on either side, with the operational specifics — body-side electronic contact count, firmware-update path, weather sealing, and whether optical glass is in the path.

Canon EF-EOS R
released 2018
Canon EF lens → Canon RF body
- 12 body-side contacts
- no firmware updates
- weather sealed
- no glass — pass-through
- Canon-first-party adapter for EF / EF-S → RF / RF-S bodies. Preserves AF, IS, electronic aperture on every EF lens since 1987.
- Three variants: plain, Control Ring (extra rotation ring), Drop-In Filter (variable ND or circular polarizer slides in).
Viltrox EF-EOS R5 (autofocus EF-to-RF)
released 2024
Canon EF lens → Canon RF body
- 12 body-side contacts
- firmware updatable
- not weather sealed
- no glass — pass-through
- Third-party alternative to Canon's official EF-EOS R; significantly cheaper, similar AF behaviour on most EF lenses.
- Firmware-updatable via USB-C, which is uncommon for the price point.

References

https://en.wikipedia.org/wiki/Canon_RF_mount

Mount specifications

Adapting Canon RF lenses onto other bodies

Adapting other lenses onto a Canon RF body

Adapter SKU teardown

Canon EF-EOS R

Viltrox EF-EOS R5 (autofocus EF-to-RF)

References

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