CPL is a commonly used filter that can remove unnecessary reflection and most of the reflection from nonmetallic, nonspherical surfaces. Improve the clarity and expression of the image, increase the concentration of color, generally used in landscape photography. Eliminate the reflected light of glass or water, make the whole picture more clear and transparent. The filter can protect the lens from dust scratches, ensure the safety of the camera. Can achieve the best reflection elimination effect through rotating the lens.