Filter (photography)
In photography, a filter is a camera accessory consisting of an optical filter that can be inserted in the optical path. The filter can be a square optical glass mounted on a holder accessory; or (more commonly) a glass or plastic disk with a metal or plastic ring frame, which can be screwed in front of the lens.Filters are commonly used in black and white photography to manipulate image contrast. For example a yellow filter will enhance the contrast between clouds and sky by darkening the latter. Orange and red filters will have a stronger effect.
Filters are less common in color photography (and even less in digital photography). A major use is to compensate the effects of inadequate lighting: e.g., the 80A blue filter corrects the orange/reddish cast of household tungsten lighting. Color correction filters are identified by numbers which sometimes vary from manufacturer to manufacturer.
Although the 80A filter is mainly used to correct for the excessive redness of tungsten lighting, it can also be used to oversaturate scenes that already have blue. The photo on the left was shot with a polarizer, while the one on the right was shot with a polarizer and an 80A filter.
Filters can be used also for special effects. A diffusion filter softens subjects and generates a dreamy haze; it can be improvised by smearing Vaseline on an UV filter.
See also: List of photographic equipment makersFilter types
This article is a stub. You can help Wikipedia by expanding it.