Canon Lens Terminology And Abbreviations – The Ultimate Guide

The Canon lens lineup has been growing for decades, as have the number of confusing acronyms and abbreviations used to describe the ever-growing list of features and new technologies. In this guide, I want to demystify the markings and letters so often appended to the end of lens names, stamped on retail packaging, and thrown around in product descriptions. Is USM better than Nano USM? Do you want a lens with SA Control or Defocus Smoothing? Can a DO lens also be an L Series lens? All of these questions and more will be answered in this guide.

Canon Lens Mounts Explained

Canon RF Mount

Canon’s RF 70-200mm f/2.8 L IS has been called a “Modern Marvel” in reviews, and it’s easy to see why.

The RF mount is Canon’s newest lens mount, designed specifically for Canon full-frame mirrorless cameras and launched in September 2018 with the EOS R camera. At launch, Canon unveiled four new RF mount lenses and a set of 3 EF to RF adapters to allow the millions of existing EF lenses to work with the new EOS R mirrorless camera system. Since then, the Canon RF lens catalog has ballooned to over 30 lenses.

The shorter flange depth of the new RF mount, compared to the older EF mount, will make several new lens designs a possibility – something which Canon immediately demonstrated by launching the stunning RF 28-70mm f/2 L. An f/2 zoom lens in this range was previously unheard of. The new RF mount dimensions can also lead to smaller and lighter lenses, as demonstrated by the small size of the RF 70-200 f/2.8 L IS.

Most popular RF lenses: Canon RF 70-200 f/2.8 L IS Canon RF 50mm f/1.2 L | Canon RF 24-105 f/4 L IS | Canon RF 35mm f/1.8 IS Macro | Canon RF 200-800mm f/6.3-9 IS USM | Canon RF 135mm f/1.8 L IS | Canon 100-500mm f/4.5-7.1 L IS | Canon RF 24-70mm f/2.8 L IS

Canon EF Mount

Canon EF 24-70mm f/4 L IS

The EF (Electro-Focus) mount is the lens mount found on all Canon EOS digital SLR cameras (DSLRs) and all Canon EOS film cameras. Superseding the Canon FD mount, the EF mount was introduced in 1987 to allow for the design of autofocus lenses, which was not possible with the more straightforward FD mount.

Any lens with an EF mount will work with any Canon DSLR, whether the camera uses a full-frame 35mm sensor or one of Canon’s APS-C cropped sensors. EF mount lenses can also be used on Canon’s full-frame mirrorless RF mount cameras when combined with one of several available EF-to-RF adapters. Although some EF lenses have now been discontinued, Canon is still manufacturing some of the more popular ones. Of course, with over 100 million EF lenses manufactured, the second-hand market for EF lenses is also booming.

Most popular EF lenses: Canon EF 50mm f/1.8 STM | Canon EF 24-70mm f/2.8 L II | Canon EF 24-105 mm f/4 L IS II | Canon 70-200 f/2.8 L IS III | Canon EF 100mm f/2.8 L IS Macro | Canon 100-400mm f/4.5-5.6 L IS II | Canon 85mm f/1.8

Canon EF-S Mount

ef-s- mount lens

The S of EF-S stands for “Small image circle.” This lens mount was introduced in 2003 to make more cost-effective lenses for Canon’s APS-C DSLR cameras. Only the middle portion of the lens is used when a full-frame Canon EF lens is used on an APS-C camera. This means much of an EF lens’s cost and weight are wasted on an APS-C crop body camera. EF-S lenses are designed only to project an image large enough to cover an APS-C sensor and are, therefore, smaller, lighter, and cheaper.

EF lenses are backward compatible with the EF-S mount. Any EF lens can be used on an EF-S mount with no adapter. EF-S lenses are incompatible with EF mounts as their optics do not project an image large enough to cover a full-frame sensor or 35mm film, and rearmost lens elements protrude too far into the lens mount. While having more affordable lenses for crop-sensor cameras is nice, it makes the upgrade path to full-frame cameras more complicated. A move to a full-frame camera will mean a complete change of lenses if all your lenses have an EF-S mount.

Most popular EF-S lenses: Canon EF-S 24mm f/2.8 STM Pancake | Canon EF-S 55-250mm f/4-5.6 IS STM Canon EF-S 10-18mm f/4.5-5.6 IS STM Canon EF-S 18-55mm f/3.5-5.6 IS II

Canon EF-M Mount

ef-m mount lens

The EF-M mount was introduced with the first EOS M mirrorless camera. Due to a much shorter flange distance than the EF or EF-S mount, EF-M mount lenses are very small when compared to EF-S lenses, even though both are designed only to cover an APS-C sensor. EF and EF-S lenses can be used on an EF-M mount using an official Canon adapter that maintains AF and all automatic functions.

In 2023, the EOS M system, with its somewhat limited EF-M lens range, is still available. However, it doesn’t take a genius to see that the newer EOS R system is the clear future for Canon. The EF-M system will likely be discontinued shortly.

Most popular EF-M lenses: Canon EF-M 22mm f/2 STM | Canon 15-45mm f/3.5-6.3 Canon EF-M 28mm f/3.5 Macro IS STM | Canon EF-M 11-22mm f/4-5.6 IS STM | Canon EF-M 32mm f/1.4 STM

Canon FD Mount

In 1971 Canon introduced the F-1 film camera with the FD mount. This 35mm mount was used until the 1987 introduction of the EF mount and the EOS line of SLR cameras. FD lenses are manual focus only, and you can still use them today using third-party FD-to-EF lens adapters. 

Canon FL Mount

Introduced in April 1964, FL mount lenses are nearly the same as FD mount lenses. FL lenses can be used on an FD mount camera. The main difference between the two is that the older FL mount lenses need to be metered with stop-down metering. Metering with a wide-open aperture is not possible with an FL mount lens.

PL Mount

pl mount lens
Canon CN-E PL mount lens

With the 2012 introduction of the Cinema EOS camera line, Canon moved into the professional film production market. With that, they added the cinema industry-standard PL mount to some of their cameras. PL mounts are only available on higher-end Cinema EOS cameras.

Alongside the introduction of the Cinema EOS camera line, Canon also introduced a line of lenses that have the option to be fitted with a PL mount or an EF mount. The PL mount is very robust and much stronger than typical DSLR or mirrorless lens mounts since it is designed to work with cinema lenses that can weigh up to 30 lbs. Note that these lenses are much more expensive than standard mirrorless lenses. For example, the PL mount Canon 50-1000 is over $70,000!

Most popular PL lenses: Canon CINE-SERVO 25-250mm T2.95 Canon CINE-SERVO 17-120mm T2.95 | Canon CINE-SERVO 15-120mm T2.95-3.9

Canon Lens Types

Canon L Lenses

Available in EF and RF lens lineups, Canon’s L lenses can be distinguished by the prominent red ring around the front. These L series lenses represent Canon’s top-of-the-line, professional-grade optics, and in the modern RF lens lineup, their focal lengths range from the unique ultra-wide RF 10-20mm f/4 L IS right up to the super-telephoto RF 1200mm f/8 L IS.

Shorter L zooms and prime lenses are black, but the 70-200mm, 70-300mm, 100-400mm, 100-500mm, and all super-telephoto prime lenses from 200mm through to 1200mm, are painted in Canon’s famous off-white color.  

Most L lenses feature Ultrasonic (USM) motors, with some newer lenses, like the RF 135mm f/1.8 L IS, featuring updated Nano USM motors. All L series lenses are weather-sealed to match Canon’s prosumer and professional camera bodies. Some L lenses, like the EF 100mm f/2.8 L Macro, feature durable polycarbonate bodies, but most are metal, with newer super telephotos featuring substantial amounts of lightweight magnesium alloy. These lenses are the cream of the crop: durable, quick to focus, incredibly sharp, and usually with a price point to match the lust factor!

Most popular L lenses: Canon RF 24-70mm f/2.8 L IS | Canon RF 14-35mm f/4 L IS | Canon RF 70-200mm f/2.8 L IS | Canon RF 100-500mm f/4.5-7.1 L IS | Canon RF 70-200mm f/4 L IS | Canon RF 15-35mm f/2.8 L IS | Canon RF 10-20mm f/4 L IS

Canon DO Lenses

Canon 400mm f/4 DO II

Canon’s Diffractive Optics lenses (DO) are built to the same exacting standards as L series lenses, but these are distinguished by a green ring around the lens barrel instead of a red one. Diffractive optical technology allows using a smaller number of lens elements by utilizing optical elements that bend the light much more than traditional glass elements from other lenses, which generally use refraction.  

The result is a much smaller and lighter lens than an equivalent made with a more traditional optical design. Canon does not yet have an extensive range of DO lenses, the most popular by far is the EF 400mm f/4 DO II (one of my all-time favorite Canon lenses). Many DO lens patents have been filed in recent years, suggesting that Canon has finally perfected this technology to its satisfaction and is getting ready to roll it out to a much more comprehensive range of lenses.

Two other lenses in the Canon catalog use diffractive optics. Canon says that the RF 600mm f/11 STM and the RF 800mm f/11 use “gapless dual-layer diffractive optics.” However, these lenses are not outwardly labeled as DO lenses, likely to avoid confusion with future much higher-end DO lenses to be released in the telephoto lineup.

Most popular DO lenses: Canon EF 400mm f/4 DO IS II Canon EF 70-300mm f/4.5-5.6 DO IS

Canon Macro Lenses

Canon RF 100mm f/2.8 L IS Macro.

Macro lenses are designed specifically for close-up photography. For decades, the definition of a macro lens was one that featured a magnification ratio of at least 1:1 (1x). For some reason, in recent years, it has become common for lens manufacturers to launch lenses with a 1:2 (0.5x) magnification ratio, also labeled as “macro.”

Canon currently has three 1:2 macro lenses in the RF lineup with 24mm, 35mm, and 85mm focal lengths. 1:2 is an impressive magnification that will yield interesting close-focussing compositions. Still, I would encourage you to consider these lenses better suited to general-purpose photography. If you seek a dedicated macro lens for insects, plants, reptiles, and other small animals, a proper macro lens like the RF 100mm f/2.8 L IS Macro is the way to go. In fact, this lens delivers beyond the minimum 1:1 macro definition, offering an exceptional 1.4x magnification. It also delivers one of the best cost-to-sharpness ratios in the RF lens lineup.

On top of regular macro lenses, Canon also has three EF mount tilt-shift macro lenses introduced in 2017. I’ll save the discussion of these for the next sub-section dedicated to tilt-shift lenses.

Most popular macro lenses: Canon RF 100mm f/2.8 L IS Macro | Canon RF 35mm f/1.8 IS STM Macro | Canon RF 24mm f/1.8 IS STM Macro | Canon RF 85mm f/2 IS STM Macro | Canon EF 100mm f/2.8 L IS Macro

Canon TS-E (Tilt-Shift) Lenses

Canon 17mm TS-E
Canon 17mm TS-E

Tilt-shift lenses are manual focus lenses that allow you to alter the angle of the plane of focus relative to the camera’s sensor. Usually, the plane of focus is parallel to the sensor, but the tilt controls of a TS-E lens allow you to position it anywhere between parallel and perpendicular. The shift mechanism corrects the keystone effect of looking upwards at tall objects, like buildings or trees.  

Architectural photographers love these lenses for the shift functionality, and landscape photographers love them for the tilt function, giving them perfect focus to the horizon with a much wider aperture than you would typically need from a regular lens. Product photographers also use them to ensure sharp focus on products from front to back, even when shooting at close distances.

TS-E lenses are mechanically complex lenses with many moving parts, and as such, they are costly. In 2017 Canon launched their first TS-E Macro lenses with the TS-E Macro 50mm, The TS-E Macro 90mm, and the TS-E Macro 135mm. Currently, there are no tilt-shift lenses for the RF mount. Users of EOS R cameras will need to use one of the EF mount TS-E lenses along with the Canon EF to RF mount adapter. Since tilt-shift lenses are manual focus, this setup has no real disadvantage, which is likely why Canon did not prioritize RF mount TS-E lenses.

Most popular tilt-shift lenses: Canon EF 24mm f/3.5 TS-E L II Canon EF 17mm f/4 TS-E L  | Canon EF 90mm f/2.8 TS-E L Macro | Canon 50mm f/2.8 L TS-E Macro

Canon MP-E Lenses

There is only one MP-E lens in the Canon lineup, the EF 65mm f/2.8. This lens is unique because it allows an incredible magnification for “super macro” photos. Usually, a lens is considered a macro lens when it can achieve a 1:1 magnification ratio, but the MP-E takes that from 1x to 5x. If you need to photograph a fly’s eye or the head of a pin, this is the lens you want.

The lens is also unique because it doesn’t have a focus ring. The only control on the lens allows you to adjust the magnification; from there, you need to alter the focus by physically moving the lens backward or forward. With such high magnification, the depth of field produced by this lens is incredibly shallow, to the point where focus stacking is needed to get any good result. This is a fun lens to try but one of the most technically challenging to create great results.

Only MP-E lens: Canon EF 65mm f/2.8 1-5x MP-E

Canon CN-E (Cinema EOS) Lenses

Canon CN-E 35mm t/1.5 L F

Canon CN-E lenses are designed for professional filmmakers, documentarians, and the cinema industry. Each lens is available with either an EF mount or a PL mount; some can have these mounts exchanged at Canon service centers. CN-E lenses all have a distinctive black and red design and are considered to be L series lenses with an exceptional optical performance and superb build quality.

CN-E lenses, primes, and zooms are extremely expensive compared to DSLR still photography lenses. CN-E prime lenses start at around $5000, and CN-E zoom lenses go to $70,000+. CN-E lenses are only manual focus and feature a manual aperture control ring.

Most popular CN-E lenses: Canon CN-E 35mm T1.5 L F | Canon CN-E 50mm T1.3 L F | Canon CN-E 24mm T1.5 L F | Canon CINE-SERVO 15-120mm T2.95-3.9 | CN-E 45-135mm T2.4

Canon CN-R (Cinema EOS) Lenses

Canon CN-R 35mm T1.5 L F

Canon CN-R lenses feature an RF mount and are designed for professional filmmakers, documentarians, and the cinema industry. Currently, the CN-R lineup consists of seven prime lenses, which, aside from the lens mount, are essentially the same as the old EF mount CN-E primes. The only difference is their direct compatibility with the Canon RF mount-no need to use a mount adapter.

Most popular CN-E lenses: Canon CN-R 35mm T1.5 L F | Canon CN-R 50mm T1.3 L F | Canon CN-R 24mm T1.5 L F | 

Canon Sumire Lenses (Cinema EOS)

Canon Sumire lenses are variations of the EF mount CN-E prime lenses that feature a slightly softer look and a creamier bokeh at wide apertures. They are available in all the same prime focal lengths as the standard Canon CN-E primes: 14mm, 20mm, 24mm, 35mm, 50mm, 85mm, and 135mm.

Most popular Canon Sumire lenses: Canon CN-E 35mm Sumire T1.5 | Canon CN-E 50mm Sumire T1.3 | Canon CN-E 24mm Sumire T1.5

Canon CINE-SERVO (Cinema EOS) Lenses

CINE-SERVO lenses are canon CN-E lenses that include (removable) hand zoom controllers.  The first was the 17-120 T2.95 ($30K) and this was followed by the optically incredible 50-1000mm lens which even includes a built-in 1.5x extender to create a 75-1500mm lens! The price? Nearly $70,000! CINE-SERVO lenses are available with either an EF mount or a PL mount.

Most popular CINE-SERVO lenses: Canon CINE-SERVO 25-250mm T2.95 Canon CINE-SERVO 17-120mm T2.95 | Canon CINE-SERVO 15-120mm T2.95-3.9 | Canon CINE-SERVO 50-1000mm T5.0-8.9

Canon COMPACT-SERVO (Cinema EOS) Lenses

The first lens with the COMPACT-SERVO designation was launched in April 2016. This was the EF mount CN-E 18-80mm T4.4. At the time, Canon’s executives were quick to underline it just the beginning of this new lineup, and sure enough, it was closely followed by the launch of the matching compact CN-E 70-200mm.

This lens range is designed to fill the enormous pricing void between standard EOS lenses designed for stills photography and the regular cinema-specific CN-E zoom lenses that start at around the $20,000 mark. These more compact lenses employ the same build quality we expect in Canon L-Series still photography lenses, and they feature all the cinema-specific design elements you would hope for, like a long-focus throw and a manual aperture ring.

Unlike the more expensive, larger regular CN-E lenses, these lenses also feature image stabilization and autofocus capabilities, making them perfect for single-operator usage. COMPACT-SERVO lenses are compatible with the optional ZSG-C10 zoom control but feature a zoom rocker that is permanently fixed to the base. COMPACT-SERVO lenses are only available with an EF mount.

Most popular COMPACT-SERVO lenses: Canon CN-E 18-80mm T4.4 COMPACT-SERVO | Canon CN-E 70-200mm T4.4 COMPACT-SERVO

Canon Compact Macro Lenses

Canon only made one Compact Macro lens, the EF 50mm f/2.5. As the name suggests, this lens was smaller than the other macro lenses in Canon’s lineup. While having a very short MFD (minimum focus distance) allowed for close-up work, the native magnification was 0.5x, rather than 1x like a ‘true’ 1:1 macro. A separate, optional life-size converter was needed to change the maximum magnification from 0.5x to 1x.

Only Compact Macro Lens: Canon EF 50mm f/2.5 Compact Macro + optional life-size converter.

Canon Soft Focus Lenses

The unique Canon 135mm Soft Focus lens had a ring around it that could be turned to apply a softer “dreamy” look to your images. This look was popular in the 70s and 80s with film photography and portraiture, long before the days of Photoshop.

Although the original 135mm Soft Focus lens has long been discontinued, this kind was given something of a lease of life with the introduction of the RF 100mm f/2.8 L Macro lens. This modern lens features what Canon calls SA Control, almost identical to the spherical aberration control in the old 135mm lens. SA Control is discussed in its own section further down the page.

Only Soft Focus lens: Canon 135mm f/2.8 Soft Focus

Canon FDn Lenses

Canon’s original FD lenses featured an SC or an SSC coating, as indicated on the lens barrel. In 1978, Canon decided to re-launch its entire FD lens lineup, updating every lens to use the higher-end SSC coating. Now all sharing the same lens coating, these new FD lenses, or FDn lenses as they were called, no longer needed the coating type marked on the lens barrel. Aside from not having the SC or SSC lettering on the lens anymore, FDn lenses are identical to FD lenses.

Canon Abbreviations & Acronyms

What Does Z Mean On a Canon Lens?

Canon RF 24-105mm f/2.8 L IS USM Z

Canon lenses with a Z in the name offer Power Zoom functionality when paired with the optional Canon PZ-E2 and PZ-E2B zoom controllers. These Z lenses are designed to be a perfect hybrid between still photography and cinematography. Currently, the only Canon Z Power Zoom lens is the stunning RF 24-105mm f/2.8 L IS USM Z; however, Canon has said that this lens is the first in a new line, so we can expect more in the not-too-distant future. I’d bet on a 70-200mm f/2.8 L IS USM Z being the next to receive the Power Zoom treatment.

The only Canon Z lens: Canon RF 24-105mm f/2.8 L IS USM Z |

What Does ASC Mean on a Canon lens?

ASC coatings are used on L series RF lenses.

ASC stands for Air Sphere Coating and was first introduced in 2014 with the EF 100-400mm f/4.5-5.6 L IS II launch. The Air Sphere Coating coating is designed to prevent flare and ghosting in backlit situations. With Canon’s focus now on the growing RF lens line, the ASC coating has been used on all RF L series lenses. You will not see the ASC lettering written on lenses, although it does appear on the retail packaging and in Canon’s lens specifications.

Most popular lenses with ASC: Canon RF 24-105mm f/4 L IS | Canon RF 50mm f/1.2 L | Canon RF 28-70mm f/2 L | Canon RF 135mm f/1.8 L IS

What Does BR Mean on a Canon lens?

BR optics are used in the RF 85mm f/1.2 L.

BR stands for Blue Spectrum Refractive and is a newer type of organic lens element first introduced with the EF 35mm f/1.4 L II. This BR element is designed to significantly reduce chromatic aberration and mitigate traditional optical materials’ difficulties with correcting blue wavelengths. BR lenses exhibit reduced blue/purple fringing chromatic aberrations. BR optics are also used in the DS and non-DS versions of the RF 85mm f/1.2 L lens.

Most popular BR lenses: Canon RF 85mm f/1.2 L | Canon RF 85mm f/1.2 L DS | Canon 35mm f/1.4 L II 

What Does SA Control Mean on a Canon Lens?

SA Control stands for Spherical Aberration Control. This feature was first introduced in 2021 with the launch of the RF 100mm f/2.8 L IS Macro lens. An additional ring behind the focus ring actuates a pair of internal cams that shift focus groups to control the shape and character of the foreground and background bokeh. At the same time, this feature also adds a smooth, dreamy soft-focus look to the image.

SA or SA Control does not appear directly in the official name of the lens, although you will find it listed in the specifications and features of lenses that have it, as well as seeing it on the retail packaging.

If any of this gives you a sense of deja vu, perhaps you have memories of Canon’s now-discontinued EF 135mm Soft Focus. This much older and oft-forgotten lens also had a ring that allowed you to control spherical aberration to some degree.

Most popular SA Control lenses: Canon RF 100mm f/2.8 L IS Macro 

What Does DS Mean on a Canon Lens?

DS stands for Defocus Smoothing, and it first appeared in the RF 85mm f/1.2 DS that was launched at the end of 2019. A regular non-DS version of the lens was also announced, so Canon users have a distinct choice to make if they purchase the traditionally perfect-for-portraits 85mm f/1.2 lens for the RF mount.

Defocus Smoothing is Canon’s term for a lens with an apodization filter built into it. The apodization filter is a circular graduated neutral density filter that sits behind the lens elements and helps to smooth the transitions of out-of-focus areas in the image, particularly “bokeh balls.”

This video does a good job of demonstrating the function in Canon lenses:

Defocus Smoothing has a noticeable visible effect on the bokeh of images shot at wide apertures. Still, the neutral density of the filter uses up some of the available light that’s coming into the camera. Canon says the effective light loss can be “up to 1.5 stops”. This means that while you are shooting at f/1.2, because the f-number is a function of the lens’ physical properties, the light that reaches the sensor would be equivalent to a T2.5 lens.

So, a DS lens will give you the best bokeh, but you might have to compensate for your exposure by using a higher ISO or a slower shutter speed than what you would use if you were shooting with the non-DS version of the same lens.

Most popular DS lenses: Canon RF 85mm f/1.2 L DS

What is IS on Canon Lenses?

Lenses that feature optical image stabilization carry the IS designation. This technology uses a system of gyros to counteract your movements and move the lens groups inside the lens to adjust for lens shake. The result is that you can handhold your lenses at much lower shutter speeds and still maintain a sharp image.

Current technology allows up to a 5-stop stabilization effect, meaning that you can handhold your lens at a shutter speed up to 5 stops less than you’d be able to without the technology. It helps low-light shooting of static subjects and is popular with travel photographers who have to shoot in available light, and sports or wildlife photographers that use longer focal length lenses.

Most popular IS lenses: Canon RF 24-70mm f/2.8 L IS | Canon RF 15-35mm f/2.8 L IS | Canon RF 70-200mm f/2.8 L IS | Canon RF 100-500mm f/4.5-7.1 L IS | Canon 100-400 f/5.6-8 IS

What Does USM Mean on Canon Lenses?

A lens with the USM designation means it features Canon’s UltraSonic Motor technology. Over time, this has now found its way into many of Canon’s current RF mount lenses. USM lenses are faster to focus, and the motors are also very quiet, though not as quiet as STM motors. Nonetheless, they are quiet enough to be helpful in wedding shooting and wildlife photography, where a certain amount of discretion is a benefit.

Most popular USM lenses: Canon 100-400mm f/5.6-8 IS USM Canon 100-500mm f/4.5-7.1 L IS USM | Canon RF 100mm f/2.8 L Macro IS USM | Canon RF 24-105mm f/4 L IS USM

What is Micro USM in Canon Lenses?

Micro USM is a cheaper version of the USM design to be included in low-end and kit zoom lenses. It is noisier than USM, slower, and does not allow manual focus override (apart from the 50mm f/1.4).  Despite being a lower grade of motor than USM, it’s still a considerable improvement over previous motor types, which were much slower and much noisier. These older motors are discussed further down the page.

Most popular Micro USM lens: Canon EF 50mm f/1.4 USM

What Does DC Mean on Canon Lenses?

The acronym DC stands for Direct Connect. Some of Canon’s older or more budget-friendly lenses use a geared DC motor. Unlike USM or Micro USM lenses, lenses with a DC motor do not offer Canon’s full-time manual focusing feature. DC motors are much slower to focus than USM and are much noisier. There are no Canon RF lenses with DC motors, so it appears that Canon has moved on from this aging AF motor type.

Most popular DC lens: Canon EF 75-300mm f/4-5.6 III

What Does STM Mean on Canon Lenses?

STM stands for Stepper Motor, and this specific focus motor design was introduced to create a quieter and smoother focus for lenses used to record video. STM lenses use a focus-by-wire system, which means that the focus ring controls a motor that moves the internal lens elements. The benefit is a quieter lens, but you lose that nice tactile focusing feel for manual focus. STM focus systems are cheaper to make than USM and are usually found on the cheaper lenses in the Canon RF lineup.

Most popular STM lenses: Canon RF 35mm f/1.8 IS STM Macro | Canon RF 50mm f/1.8 STM | Canon RF 16mm f/2.8 STM | Canon RF 85mm f/2 IS Macro STM

What Does the I, II, or III Mean on a Canon Lens?

The II designation represents the second version of a Canon lens. While they do not use the ‘I’ designation, it’s often used online to distinguish the older model from the newer one. In the EF lineup, there was also version III of the 1.4x and 2x extenders and version III of the 70-200 f/2.8 L IS.

What Do SC & SSC Mean on Canon Lenses?

Spectra Coating and Super Spectra Coating were introduced to Canon lenses in the days of the FD mount. SC was limited to cheaper lenses, and SSC was for more expensive ones. The coating is applied to optical lens elements to increase contrast and decrease reflections and flare. These days, all Canon lenses are coated with complex multilayer coatings, so the SSC designation is no longer in use.

What Is SWC on a Canon Lens?

The Subwavelength Coating helps to significantly reduce flare and ghosting and is the successor to the SC and SSC coatings.

What Was AFD In Canon Lenses?

AFD stands for Arc Form Drive. AFD was Canon’s first autofocus motor technology and is no longer a part of any lenses in the lineup. As you can imagine, these lenses were much slower to focus and noisier than current lenses. Interestingly there was no manual focus override on AFD lenses. If you wanted to focus manually, you had to disengage the AF/MF switch. Today’s lenses allow us to override AF and use the focus ring whenever we want.

What Was MM In Canon Lenses?

After the development of the AFD motor, Canon set about making a cheaper version to include in kit zoom lenses and other low-end optics. The MM motor is the result, and it was even noisier and slower than the AFD motor and, again, features no manual focus override.

What Does KAS S Mean on a Canon Lens?

Lenses that carry the KAS S marking are CN-E cine lenses that have a servo controller for smooth zoom, iris and focus control.

Most popular KAS lenses: CN-E18-80MM T4.4 L IS KAS S  CN7x17 KAS S Cine-Servo 17-120mm T2.95

What Is a Canon VR Lens?

Canon RF 5.2mm f/2.8 L Dual Fisheye 3D VR Lens

VR lenses are Stereoscopic lenses designed for virtual reality productions and compatible with Canon’s EOS VR Utility software. There is only one Canon VR lens, the bug-eyed RF 5.2mm f/2.8 L Dual Fisheye 3D VR.

Only Canon VR lens: RF 5.2mm f/2.8 L Dual Fisheye 3D VR

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Professional photographer based in Yukon, Canada, and founder of Shutter Muse. His editorial work has been featured in publications all over the world, and his commercial clients include brands such as Nike, Apple, Adobe and Red Bull.

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11 thoughts on “Canon Lens Terminology And Abbreviations – The Ultimate Guide”

    • You are correct, the DC abbreviation is missing from this list. Thanks for pointing it out, I will make a note to add something. Cheers! Dan

  1. Thank you so much for educating us with appropriate information. Wish you all the best for your future success.

  2. This was super helpful to me. I’ve been taking photos for a long time as a hobby but I’m now ready to upgrade. I own a Canon 7D. I’m wanting to take photos of cowboys working on the ranch, specifically during branding time. Do you have a suggestion? My budget needs to stay under $2000 preferably. Thanks!

  3. Very good articles but you overlooked Canon two types of lenses from a long time ago. They are S lenses, screw mount, and R lenses, grandfather of all lenses.

    I have few R lenses on my shelf and they are superb designed that lead future of FL, FD, and FDn. You should include in your article.

  4. You can check old Canon lenses as follows:

    S lenses
    R lenses Scroll down until you see “Canonflex” and R-Series Lens”

    Canon made a real moron because there will be a conflict with RF and R lenses from now and on. Canon should not use the suffix “R” as it reserved for the Super Canomatic or R series. Hopefully, they will need to change to replace the “R” with another suffix.

    Now, you realize Nikon was not first to use the f/0.95 lens. Canon already had it for the rangefinder cameras, Canon 7 or 7s, and others. This lens was the S lens family.

  5. Obrigado pelo trabalho aprimorado ! Poderia abordar posteriormente sobre as nano USM, mais especificamente 70-300, se ela é uma boa lente.


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