The Mark III edition of this Canon 1.4x Extender, or teleconverter, is the latest (and probably last) in the EF-mount series, designed for Canon cameras and compatible EF-mount Canon telephoto lenses.

Just like with any 2x teleconverter, the focal length of the attached lens is doubled, with a consequent aperture reduction of two f/stops. As such, a 70-200mm f/2.8 zoom effectively becomes roughly a ...