T here are five different mounts in the EOS camera system – RF/RF-S, EF/EF-S and EF-M – with each one being natively compatible with lenses that have the corresponding lens mount in their title. Adapters are also available that enable a lens to be fitted on a camera with a different mount, but not in all cases. It can be a little confusing if you’re new to the Canon EOS system, but we explain the permutations in detail below.
There are also some lenses that don’t list the lens mount in their name. Canon’s TS-E lenses are tilt-shift lenses designed for the EF mount, for example. But as they are manual focus only, they don’t have the EF (Electro Focus) prefix. It’s the same deal with the MP-E 65mm f/2.8 1-5x Macro Photo lens. It’s a high-magnification manualfocus lens, but it’s equipped with an EF mount. All of these lenses can be fitted directly on to full-frame and APS-C DSLRs, and with the addition of a mount adapter, they can also be used on EOS M bodies and both full-frame and APS-C cameras in the EOS R mirrorless system.