The Canon EF-EOS M is a lens mount adapter that lets you use full-size Canon EF and EF-S DSLR lenses on smaller, mirrorless Canon EOS M cameras, bridging the gap between the larger lens system and the compact M-series bodies, while maintaining autofocus, aperture control, and image stabilization for extended creative options. It essentially expands the EF-M system with the vast range of EF/EF-S lenses.