Circular polarizing filters, namely circular polarizing filters. It is mainly used to eliminate polarized light, increase color concentration, deepen sky blue, highlight white clouds, and eliminate reflected light on non-metallic surfaces such as glass or water surface. It can also reduce the soft focus caused by atmospheric fog in landscape photos, but does not change the tone balance of the whole picture. Linear polarizer, also known as ordinary polarizer, is marked in English as l-pl (UNEAR Polarizer) or PL-L (polarizing F, ilter linear), pllineat, PL, pol, CPL. CPL structure: it is divided into two pieces. When in use, the back piece is screwed in front of the lens group in front of the lens, and the front piece is rotated
