The Metabones Contarex to E-Mount Speed Booster ULTRA Adaptor is an improved speed booster that integrates 5 element/4 group optical design and yields ultra-high index tantalum-based glass. This Speed Booster ULTRA adapts Contarex to E-Mount Camera and for that, increases the maximum aperture by one f/stop and as well increases angle of view by 0.71x. It comes with a detachable tripod foot made to be compatible with Arca Swiss, Markins, Photo Clam ball heads. Metabones adaptors are built to have black matte interior and black exterior to minimize the internal reflection and maintain the optical quality of the lens. Product Features in Detail Maximum aperture Increase maximum aperture by 1 stop. MTF Increase MTF. Wider lens Makes lens 0.71x wider. Ultra-high index tantalum-based optical glass Advanced 5-element/4-group optical design incorporating ultra-high index tantalum-based optical glass by Caldwell Photographic in the USA. Detachable tripod foot The tripod foot is detachable and compatible with Arca Swiss, Markins, Photo Clam ball heads. Made of brass, precision-machined and plated with chromium Both camera-side and lens-side of the adapter are made of brass, precision-machined and plated with chromium. Satin surface finish Satin surface finish - just like your OEM lens and camera mounts. Precise fit and solid connectionLens has no play, gap or wiggling when mounted on adapter and no adjustments are required to fit your lens. Reaches infinity focus Designed to reach infinity focus while maintaining the correct registration distance required to maintain optical quality of CRC lenses or lenses with floating elements. True electronic integration of aperture diaphragm True electronic integration of aperture diaphragm - let camera automatically choose aperture in P or S exposure modes, or dial in yourself on the camera body in A or M modes. EXIF data EXIF data such as lens identification, focal length and aperture.