Generic Focal Reducer Speed Booster lens adapter work for Canon FD to Micro 4/3 M4/3Camera The focal reducer/ speed booster converts fullframe lenses into APS-C lenses. The advantage is to get the fullfame field of view onto the APS-C sensor. Increase exposure to 1 stop, and you can use faster shutter speed to shoot an image. Works fine, closely combined with the bayonet smooth, like the original lens. Full manual operation, manual focus, manual iris adjustment can be achieved with body manual exposure, aperture priority exposure, combined infinite focus. Compatible with: Canon FD Lens; Micro Four Thirds 4/3 Camera