Canon · Mirrorless mount

Canon EF-M — flange distance, protocol, and adapter compatibility

Canon's APS-C-only EOS M mirrorless mount, discontinued in 2023 in favour of RF/RF-S. EF and EF-S lenses adapt via the EF-EOS M adapter with full AF and IS, but the M-system lens lineup itself stays small. No native EF-M ↔ RF adapter from Canon.

Mount specifications

Flange focal distance: 18 mm
Throat diameter: 47 mm
Electronic protocol: Canon EF-M
Supported formats: APS-C
Manufacturer: Canon
Introduced: 2012 (discontinued)
Status: Discontinued

Adapting Canon EF-M lenses onto other bodies

You own Canon EF-M 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
Nikon Z flange 16 mm	Mechanical MFIS lens-onlyAp. wheelvignettes	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon EF-M lens and Nikon Z body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Canon RF flange 20 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.
Sony E (incl. FE) flange 18 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	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.
Fujifilm X flange 17.7 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only 0.3 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.
Fujifilm GFX (G-mount) flange 26.7 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -8.7 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. wheel1.33× crop	Speed Booster / focal-reducer family	Flange clearance is only -1.3 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.
L-Mount flange 20 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.
Leica M flange 27.8 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -9.8 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 EF-M body

You own a Canon EF-M 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 EF flange 44 mm	Mechanical AF fullIS fullAp. electronic1.5× crop	Canon EF-EOS M	1.6× crop applies on every M-system body.
Canon EF-S flange 44 mm	Mechanical AF fullIS fullAp. electronic	Canon EF-EOS M	Native image circle for EF-M's APS-C sensor.
Canon RF flange 20 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 F flange 46.5 mm	Mechanical MFIS lens-onlyAp. wheel1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Nikon F lens and Canon EF-M 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. wheel1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Sony A / Minolta A lens and Canon EF-M 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. wheel1.9× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Fujifilm GFX (G-mount) lens and Canon EF-M body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
L-Mount flange 20 mm	Mechanical MFIS lens-onlyAp. wheel1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between L-Mount lens and Canon EF-M 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. ring1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between M42 (Pentax / Praktica screw mount) lens and Canon EF-M body.
Leica M flange 27.8 mm	Mechanical MFIS lens-onlyAp. ring1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Leica M lens and Canon EF-M body.
Pentax K flange 45.46 mm	Mechanical MFIS lens-onlyAp. wheel1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Pentax K lens and Canon EF-M body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
PL (Positive Lock) flange 52 mm	Mechanical MFIS lens-onlyAp. ring1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between PL (Positive Lock) lens and Canon EF-M body.
Canon EF (cine) flange 44 mm	Mechanical MF—Ap. electronic1.5× crop	Canon EF-EOS M	1.6× crop applies on every M-system body. Cine prime keeps electronic aperture; AF is moot.
Canon RF (cine) flange 20 mm	Mechanical MFIS lens-onlyAp. wheel1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon RF (cine) lens and Canon EF-M body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Exakta flange 44.7 mm	Mechanical MFIS lens-onlyAp. ring1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Exakta lens and Canon EF-M body.
T-mount (T2) flange 55 mm	Mechanical MFIS lens-onlyAp. ring1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between T-mount (T2) lens and Canon EF-M body.
Praktica B flange 44.4 mm	Mechanical MFIS lens-onlyAp. ring1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Praktica B lens and Canon EF-M body.
Konica AR flange 40.5 mm	Mechanical MFIS lens-onlyAp. ring1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Konica AR lens and Canon EF-M body.
Minolta SR / MC / MD flange 43.5 mm	Mechanical MFIS lens-onlyAp. ring1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Minolta SR / MC / MD lens and Canon EF-M body.
Nikon Z flange 16 mm	Speed booster MFIS lens-onlyAp. wheel1.5× crop	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.
Sony E (incl. FE) flange 18 mm	Speed booster MFIS lens-onlyAp. wheel1.5× crop	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.
Fujifilm X flange 17.7 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -0.3 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 1.3 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.
C-mount flange 17.526 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -0.5 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 EF-M 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 M
released 2012
Canon EF lens → Canon EF-M body
- 11 body-side contacts
- no firmware updates
- not weather sealed
- no glass — pass-through
- Canon's adapter from EF / EF-S onto the EOS M (EF-M) APS-C mirrorless line. Discontinued in spirit as Canon shifted M-line to RF-S in 2023.
- Full AF, IS, and electronic aperture; 1.6× crop on every M body.

References

https://en.wikipedia.org/wiki/Canon_EF-M_lens_mount

Mount specifications

Adapting Canon EF-M lenses onto other bodies

Adapting other lenses onto a Canon EF-M body

Adapter SKU teardown

Canon EF-EOS M

References

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