The Canon Remote Switch RS-60E3 is ideal for preventing camera shake for telephoto shots, macrophotography, and bulb exposures. With a two foot (60cm) cable it replicates all the functions of the camera AEs shutter-release button.   

A 60cm remote release for EOS cameras featuring an E3-type socket. The two-stage control button behaves in the same way as your camera's shutter release would, activating AF on a half-press. The switch also features a lock allowing you to lock the shutter button down for long exposure times or unattended continuous shooting.