CANON LENS TERMINOLOGY EXPLAINED: HOW TO READ A LENS NAME
You can tell a lot about a lens just by looking at its full name. Understanding what it means will be very helpful when you are trying to decide which lens to buy for your photography needs. Each lens name is made up of a series of letters and numbers that provide useful information about its characteristics and compatibilities. There are four main elements that make up every lens name: lens mount, focal length, aperture and any specific technologies used in the lens. At Canon we use specific terminology to reference our lenses and understanding this will help you choose the right lens for you. So, whether you’re a complete beginner, or want to refresh your knowledge on Canon lens specifications, use our guide to help you on your photography journey.
LENS MOUNT TYPE
At Canon we have four different types of lens mount: RF, RF-S, EF, EF-S and EF-M. Put simply, a lens mount is the interface between a camera body and a lens. This feature allows for interchangeable lenses. Depending on your camera, different lens types can be used with or without a lens mount adapter.
RF & RF-S – (eg. Canon RF 24-105mm F4L IS USM Lens)
RF and RF-S lenses are specifically designed for EOS R system mirrorless cameras.
Good to know: Cameras from the EOS R range can be used with EF and EF-S lenses, when used with an adapter.
EF – Electronic Focus (eg. Canon EF 85mm f/1.8 USM Lens)
EF stands for Electronic Focus and is Canon’s longest established lens mount. It also has the widest compatibility and works with a wide range of Canon cameras. These lenses fit the entire EOS DSLR (Digital SLR) range including:
• Full-frame sensor DSLRs
• APS-C (Crop sensor DSLRs)
Good to know: EF lenses can also be used with an EOS M (EF-M mirrorless mount) and EOS R (full-frame mirrorless mount) cameras when used with an adapter.
EF-S – Short Back Focus (eg. Canon EF-S 60mm f/2.8 Macro USM Lens)
EF-S lenses are designed for APS-C (also known as crop sensors) DSLRs and are not compatible with full-frame DSLR cameras. By designing for the smaller APS-C sensor, the lens can be made smaller and lighter. For more information on whether your camera is an APS-C or full-frame DSLR, check the specifications on the individual product description.
Good to know: EF-S lenses can also be used with EOS M (EF-M mirrorless mount) and R (full-frame mount) cameras, when used with an adapter
EF-M – EOS M Mirrorless Camera System (eg. Canon EF-M 32mm f/1.4 STM Lens)
EF-M lenses are designed specifically for EOS M (mirrorless) cameras.
Good to know: When used with an adapter, EOS M cameras can use EF and EF-S lenses.
We also have other specialist lenses including the TS-E (Tilt & Shift) and MP-E which have an EF mount. A TS-E lens allows the user to physically adjust the front of the lens, move it up and down, in order to adjust the apparent angle and plane of focus. This type of lens is mainly for specialist users and is ideal for a range of photography such as architecture, product and landscape photography.
mm – Focal Length (eg. Canon EF 135mm f/2L USM Lens)
The focal length measures the range of a lens showing its shortest and longest distance. The bigger the number (the ‘longer’ the focal length), the narrower the angle of view. This means subjects will appear to be closer to the camera.
f/ or F – Aperture (eg. Canon RF 15-35mm F2.8L IS USM Lens)
Expressed as f-numbers or f-stop, aperture is the part of the lens where you control the amount of light that goes to the camera sensor. The smaller the number, the bigger the aperture and the more light can get to the camera. Controlling the aperture can benefit you in different ways. A wider aperture will create a very blurred background but a sharp subject or foreground. For example, F2.8 lets in more light than F11. Apertures of F2.8 and below are better suited for night photography and portraits.
Written in Roman numerals, this tells you where the lens sits in terms of development. When a lens design is improved, it gets a new number. (eg. III is the newer version of II)
Technologies offer more information in terms of features your lens has, and how it can help your photography.
L – Luxury Lens (eg. Canon RF 70-200mm F2.8L IS USM Lens)
L stands for Luxury. L lenses are professional lenses with great optical quality. They are used by professional photographers and offer the ultimate quality and performance.
Good to know: L lenses usually have a red ring around the end.
DS – Defocus Smoothing coating (e.g. Canon RF 85mm F1.2L USM DS Lens)
DS lenses make the bokeh (out of focus elements) in a picture a lot smoother compared to regular lenses, bringing more focus to the subject of the photo.
IS – Image Stabilisation (eg. Canon EF-M 55-200mm f/4.5-6.3 IS STM Lens)
Image Stabilisation is a system that reduces the effects of camera shake for a sharper image. You will know if your lens has image stabilisation because there will be an “IS” in the name.
Good to know: Image Stabilisation is measured in stops. The more stops a lens has, the more effective the IS will be.
USM – Ultrasonic Autofocus Motor (eg. Canon RF 15-35mm F2.8L IS USM Lens)
This motor can be found in lots of our lenses. These lenses are fast and have a manual override, making them ideal for stills.
Though it has “USM” in the name, Nano USM has benefits of both USM and STM. It offers fast, smooth and quiet focusing, making it ideal for action photography and videography. Take a closer look at how Nano USM works.Though it has “USM” in the name, Nano USM has benefits of both USM and STM. It offers fast, smooth and quiet focusing, making it ideal for action photography and videography.
STM – Stepping Motor Technology (eg. Canon EF 50mm f/1.8 STM Lens)
STM stands for Stepper Motor. This has quieter, smoother focusing, making it ideal for filming – but is still great for photos. STM is found in many different lenses.