Friday, 16 August 2013

Canon Lens Nomenclature Explained

Canon Lens Nomenclature
Canon Lens Nomenclature

Nomenclature means devising or choosing names of things; as Canon and Nikon are the most popular brands of camera; we mainly deal with these two brands. Here let us become familiar with the naming of the products (Nomenclature) from Canon. As photographers we should be familiar with the details of the tools we use. Canon use different suffixes to identify certain lens characteristics. Here they are, along with simple explanations (wherever required) of how they help.

Canon Lens Nomenclature

DO: Diffractive Optics (DO)

Special lens elements that reduce color aberrations to the minimum, thus improving image quality. DO indicate high-performance lenses that are much smaller and lighter than traditional designs.


Denotes that the lens is designed for full frame cameras. EF lens mount is the standard lens mount on the Canon EOS family of SLR film and digital cameras. EF stands for "Electro-Focus": automatic focusing on EF lenses is handled by a dedicated electric motor built into the lens. Mechanically, it is a bayonet-style mount, and all communication between camera and lens takes place through electrical contacts; there are no mechanical levers or plungers.

EF-S :

Denotes that the lens is designed for APS-C cameras. EF-S lens mount, a derivative of the EF mount that is strictly for digital EOS cameras with APS-C sensors released after 2003. EF lenses can be mounted on EF-S bodies but EF-S lenses cannot be mounted on EF bodies.

EF-M: Lens Mount for MILCs

Canon introduced the EF-M lens mount, a derivative designed exclusively for mirrorless interchangeable-lens cameras (MILCs) with APS-C sensors. EF and EF-S lenses can be mounted on EF-M bodies via the optional Mount Adapter EF-EOS M.

IS: ‘Image Stabilization’

it helps to eliminate/reduce blur caused by camera movement during exposure. Canon Optical Image Stabilizer technology uses miniature sensors and a high-speed microcomputer built into the lens. The sensors analyze vibrations and apply correction via a special stabilizing lens group that shifts the image parallel to the focal plane. Motion blur is canceled, resulting in a sharper image. With Optical Image Stabilization, it’s like gaining up to four stops.

L: Luxury series lens. 

Canon’s high end professional lenses known as L-lenses can be recognized by a red ring around the front part of the lens. Most recent L lenses have sealing to help resist dust and water. L-lenses are typically used by professionals and serious amateurs due to their superior image quality and robust design.

  • Most L series lenses share a number of common characteristics:
  • Tough build, made to withstand trials in the field (some incorporating dust and moisture resistant rubber seals).
  • At least one fluorite or ultra-low dispersion glass element, combined with super-low dispersion glass and ground a-spherical elements.
  • Non-rotating front elements, which are optimal for some filters (e.g. circular polarizers).
  • Relatively large apertures compared to other Canon lenses in the same focal lengths.
  • Ring-type USM (ultrasonic motor) and full-time manual focusing.
  • Three additional data communication pins on Canon Extender EF compatible lenses, compared to the standard EF mount.

MP-E: Macro-Photography, Electronic aperture control


Telephoto lens with a softfocus feature has the ability to use soft focusing for smooth dreamy look. It can give razor-sharp snapshots as well as softfocus shots that do not look blurry. You have a choice of two softfocus settings. Even for softfocus shots, focusing with AF is quick and accurate.

PF: Power Focus

"a mode that allows you to drive the autofocus motor electronically instead of having to use the focus ring.""It is aimed at users shooting HD EOS Movies with their DSLRs.It means you push a button that activates the AF motor to change focus instead of turning the focus collar with your hand. In the video world, it used to be the upscale feature to add a focus ring to allow for manual adjusting of focus. Now they are adding the ability to use a power focus to move instead of manually using the ring.

STM: Lenses featuring Stepping Motor (STM)

(STM) technology allows smooth and silent auto focus. When attached to compatible bodies it will provide continuous autofocus in live view and video. Unlike USM, STM lenses use electrics to enable full time manual mode, which means focus is electronically corrected within the lens with manual focus. This means an STM lens's focus can't be retracted while the camera is off.

TS: "Tilt–shift"

"Tilt–shift" encompasses two different types of movements: rotation of the lens plane relative to the image plane, called tilt, and movement of the lens parallel to the image plane, called shift. Tilt is used to control the orientation of the plane of focus (PoF), and hence the part of an image that appears sharp. Shift is used to adjust the position of the subject in the image area without moving the camera back; this is often helpful in avoiding the convergence of parallel lines, as when photographing tall buildings.

TS-E: Tilt-Shift, Electronic aperture control

USM: Ultra Sonic Motor

EF lenses equipped with USM drives have fast, silent and precise autofocus operations, and consume less power compared to other AF drive motors.

There are two types of USMs, the ring-type USM and the micro-motor USM. Ring-type USM allows for full-time manual focus (FT-M) operations without switching out of AF mode. Micro-motor USM is used to bring down the cost of the lens. It is possible to implement FT-M even with micro-motor USM; however, it requires additional mechanical components, and the vast majority of micro-USM lenses do not offer such capability.

It is basic to have a knowledge of a tool one uses; mastering its operation is another thing; a photographer however skilled in using the controls; if doesn’t know the name of the knob he operates is imperfect; like a chef who cooked a tasty dish but doesn’t know what is!