Made with Hoya precision multicoated optical glass/ 7 Element design: Half of the original lens Constitution of the lens: 7 glasses4 groups;</br>Gate Array IC (Integrated Circuitry) maintains communication between the camera body and lens</br>Focus mode: full auto focus; Maginification: 2 times; Exposure factor: Approx 4 times</br>C-AF 2X TELEPLUS can make the focal length of all the Canon EF lens increased to 2 times as respectivelyand the auto-focus function of the original camera lens can be used perfectly and don't change the EXIF information.</br>C-AF 2X specially use for 100mm or more fixed focal length lens but not recommed for use in less than 60mm of short-focus lens.</br></br>Product Description</br></br>Viltrox C-AF 2X TELEPLUS is made of high-quality coated optical glass with optical design. It can make the focal length of all the Canon EF lens increased to 2 times as respectively and the auto-focus function of the original camera lens can be used perfectly and does not change the Exif information. <br> C-AF 2X TELEPLUS specifically use for 100mm or more fixed focal length lens such as 300mm f / 2.8 lens and 200- 500mm long lens perfect combination?? can be used for fixed focus lens and a tele