Kenko C-AF 2XII Teleplus Autofocus Teleconverter Lens for Canon EOS EF Mount DSLR Cameras like Canon EF 5D II 7D 1200D 760D 750D. Compatible with Canon EF-Mount lenses 100mm and above. (Ideal for 200 ~ 500mm lenses, not recommended for lenses below 60mm). It can double the focal length of original lenses. Autofocus function of the lens (AF) and will not affect Exif information. Adopts 7 optical glasses, 4 groups, the depth of field is half of the original lenses. Equipped with a USB port for firmware upgrades. A good assistant for long-distance photography. I haven't used it, the reason for selling is that I don't need it.