The Canon FTb is a 35 mm single-lens reflex camera manufactured by Canon of Japan from March 1971, replacing the Canon FT QL. 
It features a Canon FD lens mount, and is also compatible with Canon's earlier FL-mount lenses in stop-down metering mode. 
Launched alongside the top-of-the-line F-1, the FTb was the mass-market camera in the range. Its QL designation refers to its Quick Load feature introduced by the FT-QL which allows changing film in the middle of the roll to  switch to a different type, as well as making film loading easier in general.

Canon FTb QL 35mm SLR Film Camera