With the Kenko Teleplus PRO 300 DGX 1.4x AF Teleconverter full autofocus (AF) functioning is possible with lenses having a maximum aperture of f/4 or brighter. Having 1.4x magnification, the Teleplus PRO 300 is constructed of 5 multi-coated elements in 4 groups and allows a depth of field 1/1.4 of the prime lens used and retains 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.