Heres' where it all started: The Asahi Pentax, made by the Asahi Optical Co., in 1957. Its innovation was the pentaprism (5-sided prism) viewfinder that gave the sLR an erect, correct image at eye level. In fact, the name Pentax means "Pentaprism Reflex." It was so successful that it influenced the design of 35 mm SLRs worldwide for years to come and Asahi renamed itself to Pentax. They kept the name Asahi on their cameras, except for a few years when Honeywell imported Pentax into the USA.
The Canon AE-1 is a 35 mm single-lens reflex (SLR) film camera for use with interchangeable lenses. It was manufactured by Canon Camera K. K. (today Canon Incorporated) in Japan from April 1976 to 1984. en.wikipedia.org/wiki/Canon_AE-1