Kenko 2x Pro 300 Teleconverter - Canon EF fit

Placed between the camera body and lens, a teleconverter contains a set of optics that will effectively increase the focal length of any lens with which it is used. KENKO Teleplus Pro 300 converters are made with precision quality multicoated optical glass supplied by Hoya Corporation, the worlds largest manufacturer of optical glass. These glass elements are designed to match the optical quality of the prime and telephoto zoom lenses (even at the edges). The optical design of the elements and light path is wide enough not to cause vignetting.