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Image: Canon As with other brands, Canon's lenses feature many letters and acronyms in the lens names. Seeing something like Canon RF 24-105mm F4L IS USM can leave you scratching your head if you don't know what each of those things means.

Each acronym refers to something useful, though, so understanding how to decipher Canon lens names can help you quickly grasp what the lens offers without digging into specs. In this article, we'll be breaking down Canon's common lens terminology, demystifying the company's lens names.

Lens mount type

The Canon RF-S 14-30mm f/4-6. 3 IS STM PZ lens is built for mirrorless RF mount cameras.
Image: Canon

As with most first-party lens offerings, the first part of every Canon lens name refers to the lens mount. It's important to know what mount your camera uses so that you buy lenses that are compatible.

RF and RF-S

If the lens name starts with RF or RF-S, the lens is specifically designed for the company's EOS R mirrorless cameras, which use the RF mount. These lenses are not compatible with the company's DSLR cameras, which use the EF mount.

It's also important to know the difference between RF and RF-S. RF lenses are built for full-frame cameras, while RF-S lenses are Canon's APS-C lenses designed for its crop sensor cameras.

Both use the same mount, so you can use RF and RF-S lenses on any Canon EOS R camera. However, since RF-S lenses are meant for APS-C cameras, they project smaller image circles. The camera will automatically crop for you, but using such a lens on a full-frame body will only utilize part of the sensor, meaning you’ll lose the full-frame sensor’s benefits and image area. Using an RF lens on an APS-C camera, on the other hand, primarily results in a change in field of view due to the crop factor.

EF-M

EF-M lenses are for Canon’s discontinued EOS M mirrorless cameras, which use APS-C sensors. Canon officially discontinued the system in October 2023, focusing development on the EOS R lineup. . You cannot use EF-M lenses on EOS R cameras.

EF, EF-S

Lastly, Canon EF and EF-S lenses are the brand's legacy DSLR camera lenses. EF stands for Electronic Focus. These lenses work with Canon's full-frame DSLRs and APS-C DSLRs. You can also get adapters that allow you to use EF lenses on EOS R mirrorless cameras.

EF-S lenses are designed for APS-C DSLRs. They are not compatible with full-frame DSLR cameras. You can, however, use EF-S lenses on EOS M and EOS R cameras with an adapter.

Focus systems

The Canon RF 85mm F1. 4 L VCM uses a VCM autofocus system.
Image: Canon

After the focal length and aperture information, you may see various acronyms in the lens name that refer to the type of autofocus motor the lens uses.

VCM

The VCM in the lens name means it uses a Voice Coil Motor to drive autofocus. VCM autofocus systems are powerful, fast and quiet, and they are typically used in higher-end, professional-grade lenses.

USM

USM stands for Ultrasonic Autofocus Motor. These lenses offer manual focus override and fast, smooth and comparatively quiet autofocus. The USM system is typically used in Canon's DSLR lenses and its professional telephoto lenses.

Though not in the lens name beyond USM, some lenses offer a Nano USM autofocus system. Nano USM is a specific type of motor that combines attributes of both USM (speed) and STM (smoothness) technologies. These lenses are generally meant for action photography and videography.

STM

STM stands for Stepper Motor, which provides quiet and smooth autofocus ideal for video applications. Canon's consumer and enthusiast lenses typically use its stepper motor.

Optical technology and image quality

The RF 85mm F1. 2 L USM DS lens features Canon's Defocus Smoothing coating.
Image: Canon

You may see additional acronyms when a lens offers special optical technology or image quality features. These include IS, DO, DS and BR.

IS

IS stands for Image Stabilizer. As with any brand's image stabilization system, it aims to reduce the effects of camera shake to produce a sharper image. If you see IS in the name, that means it offers optical image stabilization, and you can see how many stops of stabilization it offers in the lens's description.

DS

DS, which stands for Defocus Smoothing coating, is meant to improve the out-of-focus elements (bokeh) in your photos. Canon says it makes bokeh smoother compared to lenses without this feature.

DO and BR

Both DO and BR Optics refer to lens elements. DO, or diffractive optics, are special Fresnel-style lens elements that allow for a more compact size while maintaining quality. For example, they allow Canon to make telephoto lenses, like its EF 400mm f/4 DO IS II USM, smaller than they otherwise would be without DO elements. Canon’s DO lenses often have a green ring on the front for quick identification.

Though not included in the lens name, you may see BR, also referred to as BR Optics, in descriptions of Canon lenses. BR refers to Canon’s Blue Spectrum Refractive lens element, which it says eliminates color fringing and chromatic aberrations.

Lens class and special features

The Canon RF 70-200mm F2. 8 L IS USM Z lens is part of the L lineup of professional lenses and is compatible with Canon's Power Zoom Adapter.
Image: Canon

Finally, just like other lens companies, Canon has some specific lens classes or special features that may be included in the lens name.

L

If you see an L in a Canon lens name, such as in RF 85mm f/1. 2 L USM DS, that means the lens is part of the brand's L series, which stands for Luxury Lens. L-series lenses are Canon's professional offerings, made with higher optical quality, improved weather sealing and build quality and better overall performance. They demand steeper price tags as a result. Beyond having an L in the name, L-series lenses also typically have a red ring around the end of the lens.

Z and PZ

If you see a Z in a Canon lens name, that doesn't mean it works with Nikon Z mount. Instead, it means that the lens is compatible with Canon's Power Zoom Adapter PZ-E2 and PZ-E2B. Those adapters enable motorized control of the zoom ring for smoother video work.

You may also see PZ, which stands for power zoom, in the lens name. That means the lens offers an electronic zoom mechanism instead of a zoom ring. Just like the Power Zoom Adapter, PZ lenses are ideal for video applications.

Macro, TS-E and MP-E

Canon now spells out its Macro lenses, with the name simply including the full word. If you see Macro in the name, that means the minimum focusing distance is smaller, allowing you to get closer to your subjects. Some EF mount macro lenses are labeled as MP-E, though, indicating 'Macro Photo. '

TS-E refers to tilt-shift lenses, which allow you to adjust the focal plane (tilt) and perspective (shift). Canon hasn't released any tilt-shift lenses for its mirrorless system, so all TS-E lenses are EF mount offerings.

2025-10-30 16:00