Speed Booster ULTRA has a magnification of 0.71x (“Makes lenses 0.71x wider”). Increase MTF & maximum aperture by 1 stop. Compared to original Speed Booster: Ultra has sharper corners, less distortion & reduced vignetting. Works with Full Frame lenses. Powered by camera body, electronic integration of aperture controlled by or from the camera body. More info: http://www.metabones.com/products/details/MB_SPEF-E-BM2
