Canon EOS-M (EF-M mount) adapters

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.

The M system has an 18 mm flange focal distance (compared to 20 mm for RF and 44 mm for EF and EF-S) and a 47 mm throat diameter (compared to 54 mm for EF, EF-S, and RF). 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.