Viltrox EF-E II lens adapter is a upgraded version of EF-NEX IV. By 0.71x shortening original focal length, which help to speed up focusing process by 50%. Built-in optical glasses can increase aperture by 3 stops. It is compatible for Canon EF series lens and for Sony E-mount (APS-C) series cameras. Lens adapter fits for Canon EF series lens to use for Sony E-mount (APS-C) series cameras,and it supports Auto Focus, including CDAF and PDAF. 0.71x multiply the original focal length, which help to accelerate focusing speed by 50%. Built-in 4 groups 4 glasses optical glass, aperture is increased by 3 stops, so you can better distinguish the main object and blur out background. Gold-plated copper contact enhance EXIF signal transmission; It supports USB upgrade for sustainable usage. Made of CNC precision constructed aluminum.