The new 0.64x Speed Booster reduces the full-frame crop factor of the BMCC from 2.39x to 1.53x, thus effectively transforming it into a Super-35 format cine camera. In addition, the speed of any attached lens is increased by 11/3 stops, with a maximum output aperture of f/0.80. For example, a 50mm f/1.2 becomes a 32mm f/0.80 (i.e, by using 50mm lens, the actual focal length in BMCC is 32mm x 2.39 = 76.48mm), and Sigma’s new 18-35mm f/1.8 will become an 11.5-22.5mm f/1.1. (i.e, by using 18-35mm lens, the actual focal length in BMCC is from (11.5mm x 2.39 = 27.49mm) to (22.5mm x 2.39 = 53.78mm).