Know your Canon lens mounts

Canon’s EOS system launched in 1987 with the introduction of the EF lens mount. EF (electro focus) swapped mechanical links for a series of electrical contacts to transfer info between camera and lens. EF lenses ushered in a new era of fast accurate AF. EF lenses and mounts have a red circle to ensure you can align the lens and body. Macro and tilt-shift lenses without AF, use the designations MP-E and TS-E, but fit EF mount cameras.

With the advent of DSLRs and smaller APS-C size sensors there was a need for shorter focal length standard zoom lenses. But to reduce lens size and weight it