he 24-70mm features Canon’s standard EF lens mount, and will work on all its digital SLRs regardless of sensor size.
A rubber ‘O’-ring around the mount helps prevent dust or moisture from getting into the camera
The bayonet-mount petal-type hood is provided as standard, and clicks positively into place on the front of the lens. There’s a locking button on the side to prevent it from coming off accidentally.
The hood is made from thick plastic, and lined with black felt to minimize reflections of stray light into the lens
here’s a switch on the other side of the barrel that locks the zoom in its fully retracted position (i.e. 24mm). Canon says that using this reduces the risk of damaging the lens when taking it in and out of a camera bag.