A CPL filter, or circular polarizer filter, is a glass attachment that can reduce or eliminate glare and reflections from surfaces in your photographs. It consists of two slim metallic frames that are very close to each other, and each metallic frame holds one piece of a similar glass to an ND filter. Polarized light comes from light that has been reflected off of something, and it can come from the light reflecting off an alpine lake, reflections from a coffee shop window, or even light reflecting off moisture and pollution in the atmosphere. The CPL filter filters out this polarized light, leaving you with an image that has enhanced colors and a boost in the overall contrast of the image.

A CPL filter is an essential tool in a photographers camera bag that can eliminate unwanted reflections. It is commonly used in landscape and travel photography, as it can enhance the image drastically on the fly. Just rotate the front element until the polarization effect becomes visible, and you will capture an image with enhanced colors and a boost in the overall contrast of the image. Another common use of a CPL filter is when we need to photograph through glass.

In summary, a CPL filter is a circular polarizer filter that can reduce or eliminate glare and reflections from surfaces in your photographs. It is an essential tool in a photographers camera bag that can enhance the image drastically on the fly, especially in landscape and travel photography.