As the filter is in the optical path, any imperfections – non-flat or non-parallel surfaces, reflections (minimised by optical coating), scratches, dirt – affect the image. Many filters absorb part of the light available, necessitating longer exposure. Linear and circular polarising filters reduce oblique reflections from non-metallic surfaces. There are filters that distort the image in a desired way, diffusing an otherwise sharp image, adding a starry effect, etc. Others change the colour balance of images, so that photographs under incandescent lighting show colours as they are perceived, rather than with a reddish tinge. In monochrome photography, coloured filters affect the relative brightness of different colours pink lipstick may be rendered as anything from almost light yellow to almost black with different filters.

Sometimes they are used to make only subtle changes to images other times the image would simply not be possible without them. The filter can be of a square or oblong shape and mounted in a holder accessory, or, more commonly, a glass or plastic disk in a metal or plastic ring frame, which can be screwed into the front of or clipped onto the camera lens.įilters modify the images recorded. In photography and cinematography, a filter is a camera accessory consisting of an optical filter that can be inserted into the optical path. The larger filter is a polarizer for Cokin-style filter mounts. Four photographic filters (clockwise from top-left): an infrared hot mirror filter, a polarizing filter, and a UV filter.

Distortion filters for photos