Metabones the company that brought you the speed booster and one of the first to offer electronic lens compatibility including AF for Canon lenses on mounts like Sony E Mount and Panasonic/Olympus micro 4/3rds has updated the firmware on these to have better overall compatibility with AF modes on newer cameras.
Slow motion shooters on Sony, Panasonic and other slow motion capable cameras are big fans of these adapters and speed boosters because it allows compatibility with their Canon EF glass collection. Furthermore the speed boosters enable wider field of view and an extra stop of light which is always needed when shooting high speed footage.
