Canon EF-M lens mount

The Canon EF-M lens mount, introduced in 2012, is a derivative of the Canon EF lens mount designed for use with the Canon EOS M mirrorless interchangeable-lens camera. The EF-M lens mount is one of Canon's two new systems for mirrorless cameras, the other being the RF mount.

Canon M mount

EF-M lens mount of a Canon EF/EF-S to EF-M adapter mount
Type	bayonet
Inner diameter	47 mm
Flange	18 mm

The M system has an 18 mm flange focal distance (compared to 44 mm for EF and EF-S) and a 47 mm throat diameter (compared to 54 mm for EF and EF-S). As it is designed for use with an APS-C-sized image sensor, it features the same crop factor (of roughly 1.6) as the existing EF-S lens mount.

The M system is somewhat limited as Canon has issued relatively few native lenses, listed below. There is a lack of native lenses with a large aperture, the exceptions being 22mm/2.0 and 32mm/1.4. In 2014, third party manufacturers started to present their M lenses. In addition, it is possible to use Canon EF and EF-S lenses (made for the Canon DSLRs) with an adapter. This solution reportedly works well also with regard to the autofocus, but it takes away the size advantage of the smaller M system. Suitable adapters (from EF to M or from EF-S to M) are made by Canon as well as third party manufacturers. The adapter solution is not backwards-compatible with Canon's full-frame DSLR cameras: this means that you cannot put M lenses on a non-M DSLR.[1]

Compatibility

The cameras that can use the EF-M mount are:

• EOS M
• EOS M2
• EOS M3
• EOS M5
• EOS M6
• EOS M6 Mark II
• EOS M10[2]
• EOS M50
• EOS M100[3]
• EOS M200

List of EF-M lenses from Canon

Focal length	Equivalent focal length (×1.6 crop factor)	Aperture range	Introduced	Macro	USM	STM	IS	L-series	DO	Filter size
11–22 mm	17.6 – 35.2 mm	f/4 – 5.6	2013	No	No	Yes	Yes	No	No	55 mm
15–45 mm	24 – 72 mm	f/3.5 – 6.3	2015	No	No	Yes	Yes	No	No	49 mm
18–55 mm	28.8 – 88 mm	f/3.5 – 5.6	2012	No	No	Yes	Yes	No	No	52 mm
18–150 mm	28.8 – 240 mm	f/3.5 – 6.3	2016	No	No	Yes	Yes	No	No	55 mm
55–200 mm	88 – 320 mm	f/4.5 – 6.3	2014	No	No	Yes	Yes	No	No	52 mm
22 mm	35.2 mm	f/2	2012	No	No	Yes	No	No	No	43 mm
28 mm	45 mm	f/3.5	2016	Yes	No	Yes	Yes	No	No	43 mm
32 mm	51.2 mm	f/1.4	2018	No	No	Yes	No	No	No	43 mm

Images

• 
  Mount Adapter EF-EOS M
• 
  EF-M 11–22 mm f/4–5.6 IS STM
• 
  EF-M 15–45 mm f/3.5–6.3 IS STM mounted on an EOS M6
• 
  EF-M 18–55 mm f/3.5–5.6 IS STM
• 
  EF-M 18–150 mm f/3.5–6.3 IS STM mounted at an EOS M5
• 
  EF-M 55–200 mm f/4.5–6.3 IS STM
• 
  EF-M 22 mm f/2 STM

References

1. "Canon EOS M hands-on preview". DPReview.
2. https://www.usa.canon.com/cusa/about_canon/newsroom/press_releases?pageKeyCode=pressreldetail&docId=0901e0248105d566
3. "Step Up and Explore the Wonders of Photography With the Compact Yet Powerful New Canon EOS M100 Camera". Canon U.S.A., Inc. | Press Release Details.