Canon EF Lens Mount: Everything You Need to Know

In 1987, Canon released the EOS EF mount. It became the best selling camera mount of all time. Canon has sold more than 140 million EF lenses.

Third party companies like Sigma, Tamron, Tokina, Laowa, and others also made EF mount lenses.

This article covers the 162 Canon EF lenses for full frame cameras released between 1987 and 2018.

In 2026, even though the EF mount is considered discontinued, Canon is still selling 15 lenses along with the 5D Mark IV and Rebel T7.

The mirrorless RF mount is the replacement for the EF mount.

Canon EF-S lenses are made for smaller APS-C DSLRs. They cannot be used on a full frame DSLR.

What Lens Acronyms Mean

When choosing a lens, image stabilization (IS) is one of the most important features to consider. If you plan to shoot video, look for lenses with an STM motor, which produces less focusing noise than USM motors.

• EF stands for “Electro-Focus.” It means the lens has autofocus. Canon created it in 1987 as their answer to the Minolta A-mount, which was the first popular autofocus system released in 1985.
• EF-S lenses are made for APS-C cameras. These lenses have a white square on the mount for lining up correctly.
• EF-M lenses were made for APS-C mirrorless cameras. Those cameras have been discontinued.
• EOS stands for “Electro-Optical System.” All connections between the lens and camera are electronic.
• IS stands for Image Stabilization. This helps reduce blurry photos caused by a shaky hand.
• IF stands for Internal Focus. The lens does not move in or out when focusing.
• L stands for Luxury. These lenses have a red ring around the front. They are the highest quality lenses and are made for professional use.
• USM means the lens has a UltraSonic Motor for fast and quiet autofocus.
• STM means the lens has a Stepper Motor. It is quieter than a USM lens, which makes it better for video.
• I, II, or III tells you which version of the lens it is.

EF-S and EF-M Lenses

In addition to the 162 EF lenses, there are 20 EF-S, and 8 EF-M lenses.

The Canon Museum EF Lens Wing lists every lens with specs and background information.

EF-S and EF-M lenses cannot be used on full frame EF mount cameras. With an adapter EF and EF-S lenses can be used on EF-M or RF-S cameras. There are also adapters to allow EF lenses to be used on RF cameras.

EF-M Lenses

EF vs EF-S Lenses

Cameras with a full frame EF mount cannot use EF-S lenses because of how the mount is physically designed.

Cameras with an EF-S mount can use full frame EF lenses, since the only difference is the smaller image circle the EF-S lens projects.

Nikon and Sony handle this differently. Their cameras switch to a “crop mode” when a smaller lens is used. This uses only part of the sensor. The downside is that your photos will have less detail because you are using fewer pixels.

Using Adapters with EF Lenses

The Canon EF mount has a flange focal distance of 44mm, which is the distance between the front of the lens mount and the camera’s sensor. For a lens from another system to be adapted to EF, it must have a flange distance greater than 44mm, leaving enough room for an adapter.

M42 screw mount lenses has a 45.46mm flange distance, leaving just enough room for an adapter that allows them to be used on EF cameras. Make sure to get one with electronic contacts. A “dandelion” chip enables the focus confirmation beep and allows recording basic EXIF data. Focusing will be more difficult with an adapter that doesn’t have the chip.

The older Canon FD mount has a flange distance of only 42mm, which is shorter than the EF mount. Because there is not enough physical space for an adapter, FD lenses cannot be used on EF cameras without a corrective optical element, which degrades image quality.

EF lenses can easily be adapted to Canon RF cameras and mirrorless cameras from other brands using an electronic adapter. Canon’s official option is the Canon Mount Adapter EF-EOS R, which preserves full electronic communication including autofocus and image stabilization.

EF Zoom Lenses

EF Prime Lenses

EF Extenders

Extenders multiply the effective focal length by ×1.4 (−1 stop) or ×2 (−2 stops). Compatible with selected EF lenses only — not EF-S or EF-M lenses.

Full Frame DSLR Cameras

APS-H Cameras

APS-H sensors measure 27.9mm × 18.6mm. That’s larger than APS-C, but still smaller than full frame, with a 1.3x crop factor.

They have better low-light performance and dynamic range than the APS-C cameras produced at the time. However, as production costs came down and technology improved, Canon transitioned to full frame.

APS-C Lenses & Cameras

APS-C sensors measure approximately 22mm × 15mm, compared to a full frame sensor’s 36mm × 24mm. That’s roughly 40% less surface area.

On Canon cameras, this smaller size results in a 1.6x crop factor, meaning a 50mm lens will have the same field of view as a 80mm lens on a full frame sensor.

APS-C Entry-Level Cameras

Canon EF 35mm Film Cameras

Canon also made many film cameras that used EF lenses. Here is the full list:

Canon Camera Museum EOS Film Cameras