The Simple and Easy Guide to Canon Lens Abbreviations

In the world of photography, Canon is one of the most popular brands. It has been around for almost a century and it continues to innovate and push the boundaries of technology.

The Canon lens abbreviation system is one of their best inventions in terms of marketing. It makes things easier for photographers to understand what they are buying and what it can do for them. But what exactly does each letter mean?

Here is an easy guide to understanding the Canon lens abbreviation system:

EF: Electronic Focus Motor

This stands for a motor in your camera’s lens that will automatically focus when you press the shutter button or touch on the screen. Some lenses use a ring on the outside to focus manually, but if you have this abbreviation, you don’t have to worry about it anymore! All you need to do is point and shoot!

The EF is often used as part of a larger acronym or abbreviation, such as EF-S or EF-M. The S and M stand for “short flange focal length” and “medium flange focal length,” respectively. Short flange focal length lenses are compatible with APS-C sensors (or smaller). Medium flange focal length lenses are compatible with full-frame sensors (or larger).

IS: Image Stabilization

This stands for Image Stabilization which helps prevent blurry photos due to shaky hands or movement while taking pictures. It’s especially useful when shooting outdoors or in low light conditions where it can be difficult to get steady shots without using flash or tripods in front of your subject matter.


Stepper Motor or Ultra-Sonic Motor in Canon parlance. These terms refer to the type of motor used by the lens to move its focusing group while autofocusing. Lenses with USM motors tend to focus faster than those with STM motors, but both perform well enough for most users’ needs.

This stands for stepping motor, which is another type of autofocus motor technology developed by Canon that’s designed for video recording purposes only. It provides smoother and quieter focusing capabilities when shooting.


Vibration reduction, an image stabilization system similar to IS but better suited for long telephoto shooting since it has a broader range of movement than IS does (up to 4 stops).


This is the designation for all RF-series lenses (RF stands for Ring Focus). RF lenses have manual focus rings that can be turned at any time, even when the camera is set to auto or program modes and will work with any EOS bodies. These lenses are typically cheaper than their EF counterparts because there’s no need for an aperture ring or other electronics in order to function properly.

Canon uses two different systems for naming lenses: EF and EF-S. The first number in either system refers to the diameter of the front element (also called the objective) while the second number refers to its focal length. So, for example, an EF 85mm f/1.8 lens has an objective made up of 85mm (mm = millimeters) and a focal length of 85mm (mm).

L-Series Lenses

Canon L-series lenses are professional-grade optics designed for high-resolution imaging applications such as cinema production, surveillance and scientific research. They’re expensive, heavy and require specialized accessories like geared rings and cages for mounting onto cameras or support systems.