Kenko Teleplus teleconverters can dramatically change your photos by making the object appear larger in the image and yet maintaining its high resolution and quality. This result can be achieved by simply using this lightweight and compact tele converter even if you do not have or cannot afford a good and powerful super tele lens.Kenko Teleplus HD pro DGX teleconverter is a high precision manufactured optical device to be installed between the camera body and the lens. Its purpose is to multiply the focal length of the lens according to its multiplication factor, changing your lens into a tele lens, with minimum loss of resolution and sharpness of the image. For example, a 2x teleconverter can turn a 70-200mm lens into a 140-400mm lens. Superior quality Kenko Teleplus HD PRO DGX The Kenko HD pro is a premium series of tele converters specifically designed to be used with high resolution DSLR cameras and lenses. Optical construction has been redesigned by implementing additional optical elements and by incorporating improved multi-layer anti-reflection coating to keep the original performance of high resolution cameras and lenses.A built-in microprocessor provides accurate data transfer between lens and camera and focallength and aperture values will be recorded in EXIF data and converted to the actual shooting values with the tele converter installed. Note: You can get interference in autofocus if the brightness is lower than 5.6 in the combination lens + converter. A 1.4x converter reduces the aperture by 1 step and a 2x converter by 2 steps. Check your camera manual if you are unsure of what your camera is able of.