The
Canon EF-S lens mount is a derivative of the
EF lens mount created for a subset of
Canon digital single-lens reflex cameras with
APS-C sized image sensors. It was released in 2003. Cameras with the EF-S mount are
backward compatible with the EF lenses and, as such, have a
flange focal distance of 44.0 mm. Such cameras, however, have more clearance, allowing lens elements to be closer to the sensor than in the EF mount. Only Canon cameras released after 2003 with APS-C sized sensors support the EF-S mount.