AKA: Clapper Loader, Assistant Cameraman.
The camera loader may be responsible for two things:
(1) Operating the clapboard at the beginning of a shot. The clapboard (AKA clapper board) was originally designed as a way to provide a reference for synchronising audio and vision. Modern technology has made this unnecessary but it is still used extensively. The clapboard is still useful for providing reference information.(2) Loading film stock into film magazines.