What does cpl mean?

CPL refers to circular polarizer, or circular polarizer, which is the abbreviation of circular polarizing lens. It has the function of increasing color density and deepening sky blue.

Blue, highlighting white clouds, eliminating reflected light from nonmetallic surfaces such as glass or water. It can also reduce the soft focus caused by large fog in landscape photos, but it does not change the tone balance of the whole picture.

Extended data:

The main purpose of CPL is to eliminate useless reflection on nonmetallic surfaces. Often used for landscape photos. Using CPL can eliminate glass reflection and take clear window pictures; It can also eliminate the reflection on the water surface and obtain a crystal clear charm effect.

CPL can also be used to eliminate diffuse reflection in the atmosphere and make the sky bluer and more beautiful. When the sky is photographed at a 90-degree angle with the light source (usually the sun), the effect is the best.

Baidu encyclopedia -CPL (circular polarizer for photographic equipment)