These APO Tele Converters are compatible with digital cameras, and when mounted between the lens and the camera body, they can increase the focal length of the lens by the power of 1.4 or 2. They are also compatible with the AF function, depending on the open-aperture F value of the lens being used, and they work with the AE (Automatic Exposure) function, dispensing with complicated exposure calculations. They increase maximum photography magnification by 1.4X or 2X, without any variation in the minimum focusing distance.