It is important for those of you who want to buy lenses to understand the meaning of these codes so that you don't buy the wrong lens.
EF stands for electro focus. You can use autofocus with this type of lens.
1. E.F
This code indicates a full frame lens. EF type lenses can be used by all types of cameras, digital and film cameras. Canon cameras that can use this type of lens are marked with a red dot on the mounting.
2. EF-S
The letter S stands for Short back Focus. Usually this type of lens has a very short distance at the end of the lens that is attached to the camera with a shorter sensor than an EF lens. This lens is more affordable and is mostly used for cropped sensor (APSC) cameras. Canon cameras that can use this type of lens are marked with a white square on the mounting.
3. EF-M
This lens is used for mirrorless cameras and this type has a different mounting to the EF and EF-S.
Some important things to pay attention to:
- EF lenses are made to be used on all types of cameras made by Canon. If you have an EF lens but a camera with an EF-S mounting, you can still use that lens.
- Ef-S lenses can only be used on cameras with EF-S mounting, they cannot be used on cameras with EF mounting. The tip of the EF-S lens is longer so if it is inserted into a camera with an EF mount, the tip of the lens will touch and damage the sensor.
- EF and EF-S lenses can be used on EF-M mountings using special adapters.