Solution
Canon EF-S lenses are designed for use exclusively on cameras equipped with APS-C size image sensors.
As APS-C is more compact than 35mm full size, the optical system and mechanical structure of Canon EF-S lenses incorporate features to effectively provide optimized performance for camera models such as the EOS REBEL T6i / EOS 750D.
Using a Digital Single-Lens Reflex Camera or Interchangeable-Lens Compact System Camera with an APS-C image sensor, the replacement lens's 35 mm equivalent focal length is approximately 1.6 times greater, and the angle of view is more like that of a telephoto lens as a result. For example, if a 50 mm lens is attached to a camera with an APS-C size image sensor, the 35 mm equivalent focal length will be approximately 80 mm.
Caution
Features of EF-S Lenses
The following features make it possible for Canon EF-S Lenses to achieve optimized performance while maintaining compact and lightweight designs.
Caution
The mechanical configuration of EF-S lenses prevents them from being mounted on cameras that do not support their use. In addition, a protective rubber ring is attached to the back end of EF-S lenses to prevent possible damage resulting from accidental mounting on a non-compatible camera.