Who can tell me about the different lens models and uses of Canon? What's the difference between 18- and 17-?

Canon is divided into APS-C lens with EF-S mount and Quan Huafu lens with EF mount.

The former can only be used on APS-C format SLR, while the latter can be used on APS-C and Quan Huafu SLR.

Canon lens model is generally bayonet+focal length+aperture (+anti-shake+grade).

For example, ef-s18-135mm f/3.5-5.6 is the case.

It shows that this is a special lens for APS-C, with a focal length of 18- 135mm, a maximum aperture of F3.5 at the wide-angle end and F5.6 at the telephoto end.

IS indicates that this is a lens with anti-shake.

Such as EF 24-70mm f/2.8L USM

Explain that this is a Quan Huafu lens, with a focal length of 24-70mm, a constant maximum aperture of F2.8 at the full focal length, an ultrasonic focusing motor and no anti-shake.

L stands for luxury, which is Canon's top positioning lens, with a red circle logo, good workmanship and good image quality.

Canon EF 100mm f/2.8L is USM macro.

Explain that this lens is a professional macro lens.