A polariser camera filter is similar to polarised sunglasses. Just like the name suggests, a polariser filter blocks polarised light from reaching the camera sensor or film. Because most of the polarised light in the environment comes from reflected lights for water and other shiny materials, this can be really helpful in photography as well as cinematography. These filters help you eliminate unwanted glares from the frame. Some neutral density filters also work as polariser filters. That means, they help in both cutting down the light and eliminating unwanted reflections.