What filter is cpl?

The full name of CPL is circular polarization filter, that is, circular polarizer. Mainly used to eliminate polarized light. CPL is divided into two parts. When in use, screw the back piece in front of the lens group in front of the lens and rotate the front piece. Different angles have different effects on photometry and saturation. Generally, it is used in the direction of 90 degrees from the lighting direction to maximize the effect. Generally, the secondary exposure will be reduced and the saturation will be affected. However, it should be noted that if you want to shoot beautiful underwater reflections or metallic highlights, don't use them, it will eliminate these reflections and you won't get the image you imagined; But if you want to photograph fish swimming in the water, or algae in the pond, or exhibits in the window, CPL is a good choice. Taking portraits with CPL will eliminate the highlights on the face, reduce the contrast and make people's faces look flat, depending on whether you need special effects. You need to free one hand when adjusting CPL, so it is best to use it with tripod and cable release.

If you like landscape photography and are not very professional, you can use CPL instead of nd mirror. When using, be sure to pay attention to whether the polarizer will affect the metering of the camera.