The speed booster ultra from metabones allows a canon full frame ef mount lens to be mounted onto a micro four thirds compact system camera like the previous metabones speed booster model the updated ultra has a magnification of 071x so it effectively reduces the crop factor of mirrorless cameras with dx sized sensors such as sony e mount and fuji x mount cameras from 15x to 107x however the new optical design in the ultra uses advanced 5 element4 group optical design incorporating ult