The metabones speed booster xl 064x is designed to allow a full frame canon ef lens to be mounted onto a micro four thirds mount camera such as the panasonic lumix dmc gh4 olympus e pl7 or panasonic lumix dmc gh3 using an advanced 6 element optical design this speed booster can achieve brilliant optical performance at apertures up to f08 and will reduce the full frame crop factor of the micro four thirds camera from 20x to 128x transforming them into aps h format constructed from alum