The Kenko Teleplus DGX 1.4x Teleconverter is an easy and inexpensive way to increase the abilities of your lens without the expense of purchasing and carrying additional telephoto lenses. It features genuine Gate Array IC (Integrated Circuitry) meaning that the Kenko Teleplus DGX 1.4x Teleconverter maintains communication between the camera body and lens in the same way an original manufacturer's converter would. What's more, as a DGX converter it will also display the effective focal lengths in your viewfinder, so if you're using the 1.4x converter on a 200mm lens, a focal length of 280mm will be displayed. When used with lenses with a maximum aperture of f/5.6 or greater, auto focus will be maintained. The Kenko Teleplus DGX 1.4x Teleconverter can be used with lenses with smaller maximum apertures, but they may be limited to manual focus operation. Please note: Kenko teleconverters are not compatible with Canon EF-S lenses.