The metabones speed booster allows nikon af g f mount dslr lenses to be attached to the blackmagic pocket cinema camera micro four thirds mount the 058x speed booster increases the field of view by reducing the crop factor of the black magic from 288x to 175x and it also produces the largest aperture optics currently available with a maximum output aperture of f074 the adapter features a click less manual g aperture ring and a detachable tripod foot