VILTROX Auto Focus 2X Teleconverter Extender Converter for Canon EF Mount Super Telephoto Lens -Black

The 2X Teleconverter can make the focal length of all the Canon EF lenses increased to 2 times, Built-in 4 groups, 7 pcs optics, and the exposure factor enlarge approx 4. (equals to 2 aperture). Compatible for Canon EF Mount Lens.[Notice:It only compatible with fixed focal length L-series lenses 100mm and over, as well as the EF 70-200mm f/2.8L, EF 70-200mm f/2.8L IS, EF 70-200mm f/4L, and EF 100-400mm f/4.5-5.6L.] Support lens Auto Focus function.Outstanding image quality thanks to new optical design and improved AF performance. The focus speed is really fast and can track the subject, and lock the subject flexibly and accurately. Lens coatings are optimized to minimize ghosting and flare. With the aperture adjustment lever on the adapter, you can adjust the aperture fast. With an upgraded USB firmware interface, it supports USB firmware upgrading, and through subsequent upgrades, the adapter can improve its function, and fix bugs.