For Use with Canon EOS Digital Cameras With the Kenko Teleplus PRO 300 DGX 2x AF Teleconverter full autofocus (AF) functioning is possible with lenses having a maximum aperture of f/2.8 or brighter. Having 2x magnification, the Teleplus PRO 300 is constructed from seven multi-coated elements in four groups, allowing a depth of field that is half of the prime lens used and retaining the prime's minimum focusing distance. The Teleplus PRO 300 has genuine Gate Array IC, which means that not only the converter's own data but all data sent from the camera body provide full exposure metering and electronic flash photography.