Welcome CCCWarehouse's simplified Canon Lens abbreviations introduction. We aim to give you simple answer on commonly seem lens abbreviations.
First we need to briefly explain Full Frame and APS-C Cameras
The full frame cameras uses a sensor the same size as a 35mm film camera frame – 36mm x 24mm.
The Canon APS-C sensor is smaller at 22.3mm x 14.9mm. The field of view (how much of a scene you can see through the viewfinder) is smaller when using the same lens on an APS-C format camera than it would be on a full frame camera. This effect is called the "Crop Factor". Canon APS-C cameras have a 1.6x crop factor.
Canon Full Frame Cameras are 1D X, the 5D line and the 6D line.
Canon Cameras using APS-C sensors (just a small list as an example): Canon EOS 1200D,700D,70D,7D...
EF means "electronic focus," meaning that there is an autofocus motor in the lens itself. All Canon lenses since 1987 have been EF.
Lenses marked with EF are compatible with all Canon EOS cameras, digital and film, and are designed to cover 35mm full-frame image circle.
EF-S the only difference between Canon EF and EF-S lenses is that EF-S has been designed for Canon digital cameras with APS-C sensors. Canon EF-S lenses should not (and in most cases can not) be mounted on Canon EOS film and digital full-frame cameras with 36x24mm sized sensors because of the larger mirror used in these cameras. If mounted, damaged to the mirror may be caused upon shutter actuation – it would hit the lens’ rear element. EF-S lenses feature a protective pin that stops these lenses from being mounted on a full-frame EOS camera.
In short EF lenses fits both Cameras designed for EF and EF-S lenses.
EF-S only fit Cameras designed for EF-S lenses.
Equivalent Focal Lengths for APS-C sensor cameras.
As we mentioned before, on APS-C sensor cameras, you need to consider "Crop Factor".
At 1.6x it's quite simple to work out. For example, a Canon EF 50mm f/1.8 lens produces a field of view equivalent to an 80mm lens (50mm x 1.6=80mm) when used on a APS-C sensor camera like the Canon EOS 750D. The same applies to EF-S lenses, EF-S 18-55mm is really a 29mm-88mm lens on a Canon 750D.
EF-M a newer lens format specifically designed for the Canon EOS M mirrorless camera system with EF-M mount. Just like the EF-S lenses, EF-M are designed for APS-C sensor cameras. They will only fit Canon EOS M cameras, though, thanks to shorter flange focal distance (distance between lens mount and film/sensor plane). EF-S and EF lenses can be mounted on EF-M lens mount through the use of appropriate lens mount adapters, but EF-M lenses can not be mounted on the EF mount.
USM means Ultra-Sonic Motor, meaning AF is almost silent.
STM Stepper Motor designed to minimize autofocus vibrations and noise during video recording, this autofocus motor has been gradually making its way into budget Canon lenses. The first lens to sport STM was the EF-M 22mm f/2 STM lens. Now, all EF-M lenses incorporate the Stepper Motor, but even some EF-S lenses have been updated, like the EF-S 18-55mm f/3.5-5.6 IS STM lens. STM lenses use fly-by-wire focusing, which means turning the focus ring does not physically move the elements, but tells the AF motor to do so.
IS this is Canon’s abbreviation for optical image stabilization, or simply Image Stabilizer – a piece of technology that moves some of the lens’ optical elements to counter shake and provide sharper results when slow shutter speed is used for static subject capture.
I, II, III Roman numerals in the lens name describe the lens’ generation. For example, there are two Canon 24-70mm f/2.8L lenses: the first one is the Canon EF 24-70mm f/2.8L USM, and the other one is Canon EF 24-70mm f/2.8L II USM. The only difference in the name of the lenses is the “II” designation of the second lens, which means it is the newer, updated version. Both are professional, tough L-grade lenses, but with different optics and price. Generally, if a lens gains IS – which is Image Stabilization – it drops the previous numeral and should be considered a newer release.
L standing for “Luxury”, the L designation marks Canon’s top-end, professional grade lenses with the most advanced optical formulas and high quality, complex glass elements. These lenses are built to Canon’s highest standards and often feature some sort of weather protection as well as wide aperture setting. L lenses are priced according to their quality, but some are considered budget (within reason), like the 24-105mm f/4L lens. It retails for over $1100 at the moment and can hardly be considered cheap, but for an L lens, this sort of price is very acceptable. L class lenses are easily recognized by the presence of a red ring around the front end.
There are tonnes of other lens abbreviations used by Canon, these are most common, for the rest you can look them up directly from official Canon online guide.
