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Canon Lens Abbreviations – What Do They Mean?

Canon’s been in business for over 60 years now, releasing well over 100 lenses. And for better or worse, things haven’t remained stagnant. Instead, they’ve changed their naming conventions many times over the company’s life.

Sadly that means they’ve amassed quite an enormous list of lens abbreviations and acronyms used to describe their features or technologies. But these abbreviations continue to be a string of seemingly random numbers and letters. So it’s easy for photographers to feel overwhelmed, confused, and to think they’re marketing hieroglyphics.

But, no. They have a purpose.

Lens abbreviations help you understand lens technologies and the general industry trends. So even though they appear somewhat confusing at first, they reveal quite a bit about the lens.


Nevertheless, there are a lot of terms. So this article will outline all the abbreviations Canon uses to describe its lens technologies or features. And in the end, you’ll have a clear guide to revisit whenever necessary to determine the meaning or relevance of a specific Canon feature.

What are Lens Abbreviations?

Lens abbreviations are a set of initials used to denote its characteristics. They’re usually engraved onto the body of the lens. But the more specific qualities are only found in the lens manual or the specifications page online. Even so, this information is ultimately here to let photographers know what features the lens offers and how it can affect the images they create.

Take, for example, Canon’s EF 24-70mm f/2.8L III USM.


The first sections are the easiest to understand since they describe the lens brand, focal length, and maximum aperture. But, the  “EF,” “L”, “II”, and “USM” are not immediately apparent despite how essential the information they convey is. In this case, they let us know that this is one of Canon’s second-generation Luxury EF-mount lenses with their fast and quiet Ultrasonic autofocusing motor.

But, with the general idea of what lens abbreviations are covered, let’s start tackling the ones specific to Canon.

Canon Lens Abbreviations

Canon’s had quite a bit of abbreviation over the years. So let’s first start by covering the lens mounts and formats, then move into more specific qualities and features.

Note: I’ve organized this blog post alphabetically, so you can quickly search for specific abbreviations.

Canon Lens Mounts or Formats:

Below is a chart detailing when Canon moved from one lens mount to the next so that you can see their progression since the company’s inception.


EF Mount – Electro (E) Focus (F) – is Canon’s trademark mount first introduced in 1987 and stands as their standard DSLR mount today.  With the EF Mount, Canon brought autofocus functionality to their lenses, which wasn’t possible with the previous FD mount. Any EF lens can mount on a Canon EOS series camera, be it digital or film. And while they’re designed to cover the 35mm full-frame image circle, they do work on APS-C cameras.


EF-S Mount – Electro (E) Focus (F) Small (S) – is a subset of standard EF lenses launched in 2003 designed to fit the smaller image circle of APS-C cameras. But, unlike standard EF lenses, EF-S lenses only work on Canon’s APS-C cameras, like the T8i or 90D, not their 35mm full-frame ones, like the 5D Mark IV. And Canon’s installed a protective pin to stop users from attaching these lenses, as they could damage the DSLR’s mirror.


EF-M Mount – Electro (E) Focus (F) Mirrorless (M) – is a subset of EF-S lenses designed for Canon’s EOS M mirrorless camera system. Like the EF-S line, they too fit an APS-C camera’s smaller image circle. However, Canon developed them to have a shorter flange distance, yielding a much smaller and lighter lens than the comparable EF-S variant. So you get an even more compact camera and lens setup. Even so, it, too, isn’t compatible with the EF mount.

EF-M Mount

FD Mount – Initially developed in 1971 alongside the Canon F-1, the FD Mount is a subset of lenses designed to work with Canon’s 35mm SLR film cameras. With the release, Canon brought the ability to meter at full aperture to their lenses. So, now photographers could meter a scene wide-open at the lens’s maximum aperture, a feature not possible with the previous FL mount. And this functionality made it the default lens mount system before the EOS mount and a hit amongst 35mm film photographers who relied on manual focus. However, it’s largely obsolete today and only available secondhand.

FDn Mount – Introduced in 1978, the FDn mount added the Super Spectra Coating (SSC) to the lens range. And this designation made it easier to immediately know which lenses did and didn’t have this new coating. But otherwise, this lens is identical to a standard FD lens.

FL – Introduced in 1964 alongside the Canon FX, the FL mount is a subset of lenses designed for Canon’s 35mm SLR film cameras. But, unlike its successor, the FD Mount, the FL mount lacks metering at full aperture. So photographers would have to stop down to meter the scene.

PL Mount – Positive (P) Lock (L) – Introduced in 2012 alongside the Canon C300, the PL mount is a subset of lenses designed for cinematography. This design adopts the standard PL mount, which is even more robust and fully supports cinema lenses weighing 30 lbs, far outperforming traditional EF or RF mounts. And it’s currently an industry-standard mount amongst filmmakers and the professional film production market

PL Mount lens

RF Mount – Introduced in 2018 alongside the Canon EOS R, the RF mount is a subset of lenses designed for Canon’s newest full-frame mirrorless cameras. And it comes as their replacement to the long-standing EF mount. With the RF mount, Canon shortened the flange distance, so it’s more similar to their EF-M lineup. And that change yields a smaller and lighter lens than the comparable EF variant. So we now get identical image quality without the added bulk or weight.

RF Mount camera lens

Canon Lens Ranges, Classes or Designs:

CINE-SERVO – Canon’s CINE-SERVO are specialized CN-E lenses that include a removable handle to control zoom, focus, AF, among other functions. And they’re available in Canon’s standard EF mount or the Cinema PL mount.


CN-E – Cinema (CN) EOS (E) – Introduced in 2012 alongside the Canon C300, the CN-E range is a specialized lineup of lenses designed for professional cinematography. And they’re available in both the standard EF mount and PL mount.


Compact Macro – The 50mm f/2.5 Compact Macro is a one-of-a-kind macro lens with a much smaller design than comparable Canon macro lenses. Yet, it also offers an outstanding Minimum Focus Distance (MFD) of 0.58 inches and an interesting 0.5x magnification. Together it’s quite an exciting lens for close-up images, compared to Canon’s standard 100mm EF Macro.

Compact Servo – Introduced in 2016, the COMPACT-SERVO is a series of lenses designed to fill the enormous price gap between Canon’s standard EOS lenses and their high-end cinema CN-E lenses. And they inherit a similar build quality of an L-Series EOS lens, with more cinema-specific design elements like a manual aperture ring, image stabilization, autofocus, and a long-focus throw. And they’re also compatible with an optional lens control for zoom, focus, and iris control. However, these lenses are only available for the EF Mount, not the PL mount like most CN-E lenses.

Compact Servo

DO – Diffractive (D) Optics (O) – is a subset of Canon EF lenses that use gapless dual-layer diffractive elements to bend the light more than a lens using refraction. The result is a lens with fewer internal glass elements than usual, letting them boast a smaller and lighter design than a comparable L-Series lens. Yet, they maintain the same high-end build standards as Canon’s L-Series lenses. These lenses usually use an off-white color scheme with a signature green ring around the barrel.

do mount canon camera lens

I, II, III – These Roman numerals help signify the generation of the lens, the greater the number, the newer the lens and the more updated it is. And it helps photographers know whether this is a first, second, or third-generation lens.

KAS S – These are specialized CN-E lenses targeted at sports broadcasters. But, they also have an integrated handle for zoom, focus, and iris control like CINE-SERVO lenses.


L – Luxury (L) – this designation lets photographers know that this lens belongs in Canon’s top-of-the-line range, and they mark L-Series lenses with a signature red ring around the barrel. You can find an L-Series lens in both the EF and RF mount. But, all lenses receive weather sealing, Ultrasonic AF Motors, excellent built quality, and the most advanced optical construction.

Macro – These lenses are designed for close-up macro photography since they let you focus at much closer distances to your subject than a regular lens, say less than 1 inch away. They also feature a 1:1 (1.0x) magnification ratio, letting you reproduce subjects at their true life-size.


MP-E – Macro (M) Photo (P) EF – the MP-E 65mm f/2.8 is a one-of-a-kind lens that offers up to 5x the magnification strength of traditional macro lenses. So with its variable magnification ratio (from 1-5x), you can fill the frame with something as small as a single grain of rice or the head of a pin, making it superb for macro photography.

PZ – Power (P) Zoom (Z) – a lens with this designation means it features a detachable zoom lever accessory, so you can use it to zoom smoothly.

TS-E  – Tilt (T) Shift (S) EF – is a subset of manual focus lenses that let you tilt or shift the plane of focus so it’s no longer parallel to the sensor. And that change avoids having converting lines, known as the Keystone effect, in a photo. They’re usually used for real estate and architectural photography, so the buildings look straight. But, you can also use them to create large-format panoramas.


Lens Coatings & Filters:

  • AL – Aspherical Lens – is a type of lens element designed to improve sharpness and clarity.
  • ASC –  Air (A) Sphere (S) Coating (C) – introduced in 2014, the Canon’s ASC is a lens coating that reduces flare and ghosting when shooting in backlit conditions.
  • BR – Blue (B) Spectrum Refractive Optics (R) – Introduced in 2015, the BR coating is applied to a lens element to help reduce color fringing or chromatic aberration in the blue color wavelength.
  • DS – Defocus (D) Smoothing (S) – Introduced in 2019, the DS coating is applied to a lens element to gradually reduce the light passing through it. It essentially acts as a circular graduated neutral density filter. And it creates a soft, unique bokeh effect by smoothing the edges of the image’s out-of-focus areas.
  • SC – Spectra (S) Coating (C) – is an older lens coating that increases contrast and reduces reflections and lens flare. It’s since been replaced with the newer SSC.
  • SSC – Super Spectra Coating – is a multi-layered lens coating that reduces ghosting and flare caused by surface reflections. And it also helps produce a more consistent color rendering.
  • SWC – Subwavelength Structure Coating (SWC) – Introduced in 2011, this is Canon’s latest non-reflective lens coating to reduce flare and ghosting, replacing the SSC.
  • UD – Ultra low (U) Dispersion (D) – is a lens element that corrects chromatic aberration while being smaller and offering a similar performance as a fluorite lens.

Autofocusing Motors:

  • AFD – Arc (A) Form (F) Drive (D) – is Canon’s first and oldest autofocus motor on EF lenses. It’s a small conventional motor. But, it’s quite loud and somewhat slow at both focusing and tracking subjects. It also lacks a full-time manual focus override switch.
  • DC – Direct Connect – is a geared DC motor used on Canons’ older lenses. Like the AFD, the DC motor also lacks a full-time manual focus override and is much slower than newer technologies.
  • MM – Micro Motor – used alongside AFD, the Micro Motor is a smaller conventional motor used in budget-friendly lenses. And it, too, doesn’t offer a full-time manual focus override. But, its smaller size doesn’t make its focusing quite as loud as a comparable AFD lens.
  • STM – Stepper (ST) Motor (M) – is a focus-by-wire motor designed to provide fast, quiet, and more accurate focusing than the AFD motor. And it minimizes vibrations, making it better suited for recording video.
  • USM – Ultrasonic (US) Motor (M) – is Canon’s previous top-of-the-line ring-type focusing motor. The USM is fast, quiet, and accurate. But, they’re usually not as quiet as the STM, though. Still, it features a full-time manual focus override, letting you take control at a moment’s notice. And it’s now standard across most of Canon’s lineup.
  • Micro USM – Micro Ultrasonic (US) Motor (M) – is a smaller and more simplified version of Canon’s conventional USM. But, it’s also slightly louder and slower by comparison. And it usually doesn’t offer a full-time manual focus override. But, it’s a considerable improvement over their other technologies nonetheless.

Extra Features:

  • IS – Image (I) Stabilization (S) – refers to a lens with a group of internal gyroscopic elements that move to counteract and reduce the effects of camera shake. Canon’s currently offering lenses with up to 5-stops of optical stabilization, letting you shoot at a shutter speed that’s five times lower than usual. But either way, this feature helps you take images with longer shutter speeds handheld, without worrying about reducing image quality and adding unwanted motion blur.
  • Softfocus – Only the 135mm f/2.8 has this feature, but it purposely delivers softer images due to its optical formula. And it replicates an effect once-popular amongst film portrait photographers to make skin appear more attractive.
  • SA Control –  Spherical (S) Aberration (A) Control  – Introduced in 2021, added internal cams to shift the focusing lens elements to alter the shape and style of the lenses bokeh. This feature essentially replicates Canon’s 135mm Softfocus lens mentioned above. And it gives images either a dreamy or a bubbly look.

Lens Example

Now that we’ve covered Canon’s rather exhaustive list of abbreviations, let’s test your knowledge by analyzing one of their current lenses.

Let’s look at the infamous Canon EF 70-200mm f/2.8L IS III USM. I will also include the list of other terms this lens has that aren’t officially published in its title but mentioned in the product listing. These include ASC and UD.


Based on its name, we can immediately tell a few things. First, it’s designed for full-frame EOS cameras (EF). Second, it’s an L-Series lens, making it among Canon’s professional-level lenses. That means it has a top-of-the-line construction, both optically and physically. So it likely has weather sealing and a longstanding construction, ready for abuse. We can also see this lens is now in its (III) generation, so it’s their latest release. Next, it features Optical Image Stabilization (IS), and it grabs Canon’s best autofocusing motor for quick and snappy focusing (USM). In this case, it also receives a full-time manual focus override. Lastly, it has two high-end optical coatings to reduce aberrations and improve image quality (ASC and UD).

And gathered all of this information from a single sentence.


Canon’s lens abbreviates are helpful, and they give photographers a clear sense of what their products offer. But, given Canon’s now created quite an exhaustive list of abbreviations, it’s clear why some of these terms are confusing. And it’s unlikely any of us will retain all of this information. So feel free to use this article as a reference or guide to come back to when you have questions.

Frequently Asked Questions:

What is lens abbreviation?

A lens abbreviation is a set of initials or an acronym used to describe its features and technologies. These initials are included on the lens body and the official lens name. And they help photographers quickly identify various traits about a lens.

Is EF full frame?

Yes. Canon designed EF lenses to cover the 35mm full-frame film plane or digital sensor. At the same time, EF-S is designed for the smaller image circle of their cropped sensor cameras.

What is the difference between RF and EF?

The difference is the flange distance, which is smaller on the RF mount. With a smaller flange distance, Canon could create smaller but optically superior lenses than what was possible with EF.

What is the difference between EF and EOS?

EF is a lens mount used on Canon DSLR lenses, which replaced the older FD mount used on film SLRs. EOS, short for Electro-Optical System, is a name Canon gives to any DSLR camera with this technology.