Screw-Type Mount (1946-1964)
A standard-thread-type screw mount that was used to attach lenses to Canon's early rangefinder cameras.

R Mount (1959-1963)
An innovative friction lock mount and an automatic aperture control mechanism developed by Canon. An R mount lens was attached to the camera by aligning both lens and camera in the correct position (indicated by dots) and tightening the attachment ring on the lens until the lens was securely in place.

FL Mount (1964-1974)
FL mount lenses used a friction-lock to be attached to a camera. Indicators on both the lens and camera were lined up and an attachment ring was turned until the lens was securely in place. FL lenses for the first time allowed TTL metering. However, it was required to stop down the lens to the selected aperture value during metering.

FD Mount (1970-1979)
FL mount lenses used a friction-lock to be attached to a camera. Indicators on both the lens and camera were lined up and an attachment ring was turned until the lens was securely in place. The innovation was that these lenses allowed TTL metering without the requirement to stop down the lens.

New FD Mount (1979-1989)
Lenses with the New FD mount (FDn) came with an improved locking mechanism. With previous mount systems, a lens was attached to a camera by positioning the lens barrel at the camera opening and by turning a separate attachment ring until the lens was locked in place. Lenses with the New FD mount offered a more convenient way by rotating the entire lens barrel a quarter turn until it was locked in place. The New FD mount also introduced a lens release button that ensured that the lens would not detach by accident.

EFElectro-Focus (1987-present)
At the time of its introduction, the EF mount was a revolutionary new type of lens mount that was developed for Canon's EOS series of DSLR cameras. The EF mount system offers a bayonet-style attachment system that requires a quarter turn until the lens is securely locked in place. However, the real advantage of the EF mount is the eight-pin electronic interface between the camera and the lens to exchange information (aperture control, autofocus, selected focal length, etc.) via digital signals. The EF mount system is available on all Canon EOS cameras (full frame, APS-H, and APS-C) and it supports the largest variety of lenses, including Canon's EF and EF-S as well as MP-E and TS-E series of lenses.

EF-SElectro-Focus Short Back Focus (2003-present)
EF-S is a derivative of the EF mount which was designed for lenses with a smaller image circle. EF-S lenses are attached to the EF mount of Canon's EOS series of cameras. However, they can only be used on those EOS cameras that have an APS-C sensor. The EF-S connector provides the same eight-pin electronic interface as used for the EF system.

EF-MElectro-Focus Mirrorless (2012-present)
The EF-M mount was developed for Canon's EOS M-series compact mirrorless cameras. It features a bayonet-type attachment mechanism and an electronic interface between the camera and the lens. EF-M lenses can not be used on cameras having either an EF or RF mount system.

RFRe-Imagined-Focus (2018-present)
The RF mount is Canon's latest attachment system that was developed specifically for Canon's EOS R series of mirrorless cameras. This system continues to use a bayonet-type attachment mechanism that requires a quarter turn until the lens is securely locked in place. The electronic interface has been improved and is now a 12-pin connection between the camera and the lens. Another innovation is that the RF mount has a shorter distance between the flange and the image sensor compared to all previous mount systems, reducing the overall camera size. The RF mount accepts both Canon's RF and RF-S series of lenses.

RF-SRe-Imagined-Focus Short Back Focus 2022-present
RF-S is a derivative of the RF mount which was designed for lenses with a smaller image circle. RF-S lenses are attached to the RF mount of Canon's EOS R series of cameras. If an RF-S lens is connected to a full frame EOS R camera, the camera automatically switches into a crop mode where only a reduced area of the full frame sensor becomes active. The RF-S connector provides the same 12-pin electronic interface as used for the EF system.

AFDArc-Form Drive (1987-1990)
Canon's first autofocus drive using an asymmetrical stepper motor and arc-shaped transmission gearbox. The acronym AFD is neither printed on lens barrels nor included in lens names but is only used internally in service manuals.

DC Micro Motor (1993-2016)
A very compact autofocus drive using a small direct current (DC) motor and small transmission gearbox. The description DC micro motor is neither printed on lens barrels nor included in lens names but is only used internally in service manuals.

USMUltrasonic Motor (1987-present)
An autofocus drive technology using piezoelectric ceramic elements on a ring-shaped stator to generate ultrasonic vibrations that ultimately turn a ring-shaped rotor. If a lens uses this technology, the acronym USM is always included in the lens name. In addition, many lenses using this ring-type USM have the term Ultrasonic printed on the side of the barrel.

Micro USMMicro Ultrasonic Motor (1992-2016)
Another autofocus drive technology using piezoelectric ceramic elements but with a different motor construction that is much smaller than the ring-shaped USM. If a lens uses this technology, the lens name does not include the term Micro USM but rather the more general acronym USM. In addition, lenses using the Micro USM usually have the term Ultrasonic printed on the barrel. The exact type of USM system a lens uses is typically described in the service manual.

Nano USMNano Ultrasonic Motor (2016-present)
Another autofocus drive technology using a highly miniaturized slider that uses piezoelectric ceramic elements to vibrate. This vibration is then used to move the slider in a linear way. If a lens uses this technology, the lens name does not include the term Nano USM but rather the more general acronym USM. The description Nano USM is usually printed on the side of the barrel.

STMStepper Motor (2012-present)
A very small 2-phase stepper motor is used to drive the autofocus system inside the lens. Canon uses two different transmission types, the lead-screw-type and the gear-type. If a lens uses this technology, the acronym STM is always included in the lens name.

VCMVoice-Coil Motor (2024-present)
Canon's latest autofocus drive technology using electromagnetic coils and permanent magnets to slide the focusing lens along two linear guide rails. If a lens uses this technology, the acronym VCM is always included in the lens name.

ISImage Stabilizer
An image stabilizer is a technology that is able to compensate camera shake by quickly counter-shaking a stabilizing lens element. This feature helps to maintain sharp images at slower shutter speeds, providing more flexibility in various shooting conditions. Canon lenses that are equipped with an image stabilizer usually have IS in their name and the term image stabilization printed on barrel.

EMDElectromagnetic Diaphragm
An electromagnetic diaphragm is an element that controls the aperture of the lens. It is located inside the lens barrel and is driven by a small stepper motor. This motor turns thin diaphragm blades which are normally fully open and quickly snap into the set aperture position once the shutter release button is pressed on the camera.

AFAutofocus
This is a technology used in photographic and videographic lenses that automatically adjusts the lens to achieve proper focus on a subject. This automatic adjustment relies on different types of autofocus drive motors.

MFManual Focus
This is an optional setting on nearly all Canon lenses that allows the photographer to adjust focus by turning a focusing ring.

PFPowerfocus
A mode primarily used when shooting video that allows the user to electronically control the autofocus motor using the playback ring of the lens to change the focus in a smooth way.

Fluorite
Fluorite is a naturally occurring crystal with some properties that make it an excellent optical material for lenses. In particular, fluorite causes an extremely low dispersion which is a unique feature to correct lenses for chromatic aberrations and achieve better overall image quality. At the end of the 1960s, Canon succeeded in artificially crystallizing calcium fluoride (CaF₂) into fluorite, but still the production of fluorite lens elements remained expensive. For that reason, fluorite lens elements are primarily used in high-end lenses.

UDUltra-low Dispersion
This is the name of some elements in Canon lenses that are made of specialized optical glass. These special glass elements cause very low levels of dispersion – although not quite as low as fluorite – which helps to minimize chromatic aberrations and achieve better overall image quality. Using optical glass, rather than fluorite, is more cost-effective, and therefore Canon intensified their use of these high-performance optical glasses in the 1970s.

Super UDSuper Ultra-low Dispersion
The Super UD glass is a further development of the UD glass. Super UD glass has been developed in the 1990s and is still in use in contemporary lens models.

BRBlue Spectrum Refractive
Blue spectrum refractive elements describe an optical technology used in some high-end Canon lenses to minimize chromatic aberrations. BR lenses use a special optical polymer that refracts blue light more effectively, minimizing chromatic aberrations and improving overall image quality.

DODiffractive Optics
Diffractive optical elements do not refract light in a traditional way but rather use an optical phenomenon called diffraction. Canon's DO lenses are more compact and lightweight than refractive lenses and still offer high optical performance. Another benefit of diffractive optical elements is that that they help to counteract chromatic aberrations.

GMoGlass-Molded
This is an abbreviation of a specialized lens manufacturing technology used to produce aspheric lens elements.

PMoPlastic-Molded
This is an abbreviation of a specialized lens manufacturing technology used to produce aspheric lens elements.

Fluorine
This is a transparent protective coating applied to the front and rear elements of a lens. As it is highly oil- and water-repellent, this coating prevents dirt from sticking to the glass.

Power Zoom
A specific feature that is only available on a few models of Canon lenses and uses a motor to control the zoom of a lens instead of manually turning the zoom ring. Power Zoom offers particularly smooth zoom adjustments, which is often beneficial for video shooting or situations where precise zoom control is desired. While some Canon lenses have the Power Zoom feature integrated into the lens barrel itself, there are also Power Zoom adapters that can be attached to the barrel of compatible lenses to motorize the zoom movement.

PZ
Canon lenses with the acronym PZ in their name have the motorized zoom control directly embedded in their lens barrel and do therefore not require an additional adapter. Older PZ lenses such as the Canon EF 35-80mm F4-5.6 PZ (1990) have dedicated zoom control buttons on the barrel. More recent PZ lenses such as the Canon RF-S 14-30mm F4-6.3 IS STM PZ (2025) feature a clean design with no zoom control buttons on the barrel as the zoom is controlled on the camera.

Z
The letter Z at the end of a Canon lens name indicates that the lens is a hybrid lens designed for both still photography and video, and that it is compatible with external Power Zoom accessories. While these lenses do not have a built-in Power Zoom motor, they are designed to work with an external motorized Power Zoom adapter to enable power zooming. For example: Canon RF 70-200mm F/2.8L IS USM Z.

DSDefocus Smoothing
Canon's DS lenses are specially designed to provide an extremely soft and feathered bokeh. This effect is achieved by applying an edge-gradiated neutral-density filter coating on one or more glass surfaces inside the lens.

SFSoft Focus
A soft focus lens deliberately introduces spherical aberration and slight blur into the image, creating a soft glow, while retaining sharp edges across areas of high contrast. Soft focus images are not out of focus but rather introduce an additional soft overlay. This feature is used by some photographers to create a playful effect and improved skin tones.

SCSpectra Coating
Spectra coating is the name of Canon's first anti-reflective coating that consisted of one layer of vapor-deposited transparent material.

SSCSuper Spectra Coating
The super spectra coating was Canon's first multi-layer anti-reflective coating that consisted of four layers of vapor-deposited transparent material.

ASCAir Sphere Coating
Unlike traditional anti-reflective coatings, the air sphere coating uses an additional layer of material that contains microscopic air bubbles. The air enclosed inside that top coating results in an exceptionally low refractive index of that layer which in turn reduces overall reflectivity (flare and ghosting) of the lens.

SWCSubwavelength Structure Coating
The subwavelength structure coating is Canon's latest development in anti-reflective coatings. Unlike previous layer-based coatings, an SWC coating consists of microscopic wedge-shaped nanostructures on the lens surface to form a graded index anti-reflective coating. This design is extremely successful in preventing reflections (flare and ghosting) from degrading the image quality.

LLuxury
A Canon lens that has the letter L included in its name is a premium version that is designed for professional use. L-series lenses offer superior optical performance, high-end build quality, and exceptional durability due to robust materials and weather sealing. Canon's L-lenses are easily recognizable by their red ring around the barrel of the lens.

Macro
This term is printed on some lenses that are specifically designed for extreme close-up photography. These types of lenses are popular among photographers who specialize in capturing small subjects, such as insects or tiny plants. A lens is a true macro lens if it provides a magnification ratio of 1x life-size or higher.

Compact Macro
Same as macro. The Canon Compact-Macro EF 50mm F2.5 lens (1987) is the only Canon lens that has this description printed on its barrel.

MP-EMacro Photo-Electro
This unique Canon lens series is designed for professional macro photography, providing magnifications from 1x to 5x life-size. Unlike typical macro lenses, MP-E lenses do not focus to infinity and are intended solely for macro photography. Example: Canon MP-E 65mm F2.8 1-5x Macro Photo.

TS-ETilt-Shift-Electro
TS-E lenses are highly specialized lenses that are primarily used in architectural and product photography. These optical systems allow photographers to control the plane of focus and the perspective independently, achieving precise focus across the entire subject and preventing converging vertical lines in tall structures.

II, III, IV, V, etc.
Roman numerals behind the lens name indicate that a lens is an updated and optimized next-generation version. First generations do not have a roman number. For example: Canon EF 28-80mm F3.5-5.6 V USM.

Photography Lens
A photography lens is primarily designed for use with photo cameras. Typical features of photography lenses include image stabilization as well as autofocus drive systems.

Still Lens
Same as photography lens.

Cine Lens
Cine or cinema lenses are designed especially for cinematography. For this reason, cine lenses are equipped with video shooting features such as manual aperture rings, parfocal zoom capabilities, as well as reduced focus breathing. Traditional cine lenses do not have a built-in autofocus drive system as they are designed for manual focus to give videographers precise control during filming. However, some new generations of cine lenses do offer autofocus or electronic focus control.

Hybrid Lens
Hybrid lenses are designed for creators who shoot both photos and videos. These lenses combine features such as image stabilization, autofocus, manual aperture ring, and parfocal zoom.

Prime Lens
A prime lens has one fixed focal length that cannot be zoomed. For that reason, a prime lens only offers one field of view. Prime lenses have only one focal length written in their name, such as 100mm.

Parfocal Lens
A parfocal lens or real zoom lens can change its focal length (field of view) within a certain range. The term parfocal means that these lenses maintain perfect focus while zooming, and therefore no focus adjustment is required.

Varifocal Lens
A varifocal lens can change its focal length (field of view) within a certain range. The term varifocal means that these lenses shift focus while zooming, and therefore focus must be readjusted each time after changing the focal length setting.

Zoom Lens
Zoom is often used as an umbrella term for lenses that can change their focal length (field of view) within a certain range. These may include varifocal and parfocal lenses. Strictly speaking, real zoom lenses are parfocal and maintain perfect focus while zooming, otherwise they are varifocal lenses. Zoom lenses have a range of focal lengths written in their name, such as 24-70mm.

Constant Aperture
A zoom lens that has a constant aperture is able to maintain the diameter of its largest aperture (smallest f-number) throughout the entire range of focal lengths. This means while using the largest aperture the lens is not automatically stopping down once changing the focal length. Lenses with a constant aperture have only one f-number written in their name, such as f/2.8 or F2.8.

Variable Aperture
A zoom lens that has a variable aperture is going to reduce the diameter of its largest aperture (smallest f-number) while changing the focal length. This means while using the largest aperture the lens is automatically stopping down once zooming to certain focal length values. Lenses with a variable aperture have a range of f-numbers written in their name, such as f/4-7.1 or F4-7.1.