Extends the master lens focal length by 1.4x Outstanding image quality Highly resistant to dust and water Improved communication between lens and camera Optimised lens coatings Compatible with L-Series telephoto and telephoto zoom lenses Ideal for press, sports and nature photography, this compact extender increases the focal length of Canon L-series telephoto or telephoto zoom lens' by a factor of 1.4x, with higher AF accuracy and improved communication between camera and lens. Lens system Lens mount interface Canon EF Lens type Extender lens Lens structure (elements/groups) 7/3 Component for SLR Performance Compatibility EF 100-400mm f/4.5-5.6L IS USM, EF 135mm f/2L USM, EF 180mm f/3.5L Macro USM, EF 200mm f/2.8L II USM, EF 200mm f/2L IS USM, EF 300 2.8 L USM, EF 300mm f/2.8L IS USM, EF 300mm f/4L IS USM, EF 400mm f/2.8L IS USM, EF 400mm f/4 DO IS USM, EF 400mm f/5.6L USM, EF 500mm f/4L IS II USM, EF 500mm f/4L IS USM, EF 600mm f/4L IS II USM, EF 600mm f/4L IS USM, EF 70-200mm f/2.8L