Original: The Canon EOS (Electro-Optical System) autofocus 35 mm film and digital SLR camera system was introduced in 1987 with the Canon EOS 650 and is still in production as Canon's current DSLR system.
Simplified: The Canon EOS (Electro-Optical System) is an autofocus 35 mm film and digital SLR camera system that was introduced in 1987 with the Canon EOS 650 and is still in production as Canon's current dSLR system.