What is the difference between EOS and SLR?

EOS and SLR are the most routinely heard acronyms in the art of photography. SLR or Single Lens Reflex refers to a mechanism where a single lens is used for both looking at and snapping pictures. The term EOS was introduced by the Canon Corporation, which symbolizes that the camera is for both films and SLR's.

EOS, or Electro-Optical System, became a brand name for one of the leading camera and lens manufacturers in the world. The EOS was put on the market to incorporate an autofocusing feature into the cameras. All EOS cameras are SLR's, but not all SLR's are an EOS.