Buying a new lens for your mirrorless or DSLR camera can be a daunting task. As well as considering compatibility, budget, and size, you need to decide whether the focal range suits your needs. While our camera lens buying guide can set you on the right path with focal length, aperture range, and other key features, you might still need help decoding precisely what all those letters on a Canon lens actually mean.
Our Lens Decoder series aims to do just that — here's the Canon edition.
Canon Lens Mounts
EF — Canon's standard DSLR mount, also compatible with EOS film cameras. EF lenses work on both full-frame and APS-C DSLRs.
EF-S — Designed specifically for Canon's APS-C format DSLR cameras. The "S" stands for small image circle.
EF-M — Designed for Canon's APS-C EOS M mirrorless range. Note that Canon has discontinued the EF-M system; their current mirrorless lineup uses the RF and RF-S mounts.
RF — Canon's current mirrorless mount, used across the full EOS R range — both full-frame and APS-C format cameras.
RF-S — RF lenses specifically designed for Canon's APS-C format EOS R mirrorless cameras.
Canon Lens Series
L — Canon's top-tier lens series. The L stands for Luxury, and these lenses are built to professional standards both optically and physically — typically featuring weather sealing, fast apertures, and premium glass.
TS-E — Tilt-shift (perspective control) lenses, used for architectural photography and creative focus effects.
CN-E — Canon's professional cinema lens lineup.
Canon Optical Technology Explained
ASC — Air Sphere Coating. Reduces flare and ghosting by using a layer of air within the coating structure to minimise reflections.
DO — Diffractive Optics. Allows for a smaller, lighter lens design by using fewer elements, without compromising optical quality.
IS — Image Stabilisation. The lens includes optical stabilisation to reduce the impact of camera shake for sharper handheld images.
I, II, III — Roman numerals indicate the generation of the lens, used to differentiate updated versions of the same focal length.
Macro — The lens is designed for close-up photography, typically capable of 1:1 reproduction ratio.
SC — Spectra Coating. An anti-reflective coating applied to outer lens elements to reduce flare and ghosting and improve contrast.
SSC — Super Spectra Coating. An enhanced version of Canon's Spectra Coating anti-reflective treatment.
STM — Stepping Motor. Delivers fast, smooth, and quiet autofocus — particularly well suited to video recording.
SWC — Sub-Wavelength Coating. A newer anti-reflective coating that reduces flare and ghosting more effectively than SC or SSC.
UD — Ultra-low Dispersion glass. Known for its low refractive index and dispersion qualities, delivering high optical performance and reduced chromatic aberrations.
USM — Ultrasonic Motor. Provides fast, quiet autofocus performance — suitable for a wide range of photography and video applications.
Shop Canon Lenses at Ted's
Ready to make your next lens purchase? Browse our full range of Canon RF lenses and Canon RF-S lenses at Ted's Cameras, or visit us in-store for personalised advice from our expert team.