Canon Lens Abbreviations and Acronyms

Lens manufacturers use abbreviations to specify the features of their lenses, and as the number of abbreviations increase with the newly added features, things become quite confusing especially for photographers who are not familiar with the lens technology.

In order to make things a bit more clear, we will present the lens types and abbreviations with descriptions in alphabetical order for the most popular lens manufacturers, starting with Canon.

AFD – Arc-Form Drive: An older type of in-lens AF motor like USM but slower and noisier.

AL - Aspheric Lens: A special design lens used to minimize aberrations. Aspheric lenses can be designed more compact and lightweight then conventional lenses.

CA – Circular Aperture: Canon lenses with multiple aperture blades shaped to give as circular an iris shape as possible, effects the bokeh.

CaF2 – Fluorite Element: Very expensive material used in place of glass, offers great resolution and color accuracy. Corrects chromatic aberrations even more then Super UD. Mostly used in L-series and super-telephoto lenses.

EOS –Electro Optic System: Canon’s current SLR camera system which was introduced in 1987.

EF – Electronic Focus: Canon’s current standart lens mount designation. It is compatible with all EOS bodies

EF-S: Lens mount designation for Canon's APS-C DSLRs (EOS 300D-Digital Rebel, 350D-Digital Rebel Xt, 400D-Digital Rebel Xti, 20D, 30D, 40D). EF-S lenses are not compatible with film SLRs and DSLRs that that don’t have EF-S mount (full frame and 1.3x crop sized sensor)

E-M – Electronic Manual Focusing: Old type of USM lenses which deploys USM motor for electrically manual focusing.

FT-M – Full-Time Manual Focus: Manual focus is possible with lens in AF mode for fine adjustment of focus.

I/R – Internal or Rear Group Focusing: I/R lenses doesn’t change length and the front element does not rotate. Very useful for with a polarizer filter.

IS – Image Stabilization: Canon’s optical based stabilisation system that reduces the vibrations, works similar to VR – Nikon, OS – Sigma, VC – Tamron, O.I.S – Panasonic

L – Luxury: The designation that Canon gives to its professional range of lenses. Almost all L-series lenses have white color bodies and the red ring around the barrel.

MP-E – Macro Photo Electronic. Specialised Canon lenses designed for macro photography. MP-E lenses are manual focus and E (Electronic) refers to the electronic aperture control.

Super UD – Super Ultra-Low Dispersion glass: More effective than UD for correction of chromatic aberration

T/S (TS-E) – Tilt/Shift. These are the lenses that can be shifted and tilted to control the plane of focus and correct perspective distortion. Used especially for architectural and studio works.

UD – Ultra-Low Dispersion Glass: Special glass used for correction of chromatic aberration

USM – Ultrasonic Motor: Auto focusing motor that offers fast and silent focusing using piezoelectric elements. There are two types;

Micro–USM: Low-cost but slower, does not support fulltime manual focus.

Ring–USM: Faster and features fulltime manual focus override without switching off AF.