Canon started the confusion between EF and EF-S lenses in 2003 when they created a different lens mount on DSLR models. The lens mount varies between full frame DSLR cameras and crop sensor DSLR cameras. What is a full frame and crop sensor you say? Find out HERE. The names EF and EF-S refer to the style of lens mount that can be found on the front of your camera body.
EF lenses can be used on both the EF and EF-S style lens mounts. EF-S lenses are only compatible to the EF-S mount. To know if you have an EF-S mount on your camera body, head over to my post about the EF-S lens HERE. EF lens mounts look like this with a single red dot on the mount rim.
EF lenses also come with a few extra features that the EF-S models do not have. These features also make EF lenses significantly more expensive than their EF-S younger brother. The distance scale window, focus distance range limiter switch, soft focus ring, and image stabilizer features can be found on certain EF models.
Just because the EF lenses are more expensive and come with more features does not mean that they take better photographs. You must learn to use them for what they were made for. However, the features can help you in specific situations.
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