A camera filter is an optical lens often enclosed in a circular holder that can be attached to a camera's lens by screwing it on. Individual filters alter images in a certain way based on the effect or change the lens is designed to produce. Computer software can also mimic many filter effects on images already taken when they are stored locally.
Color Manipulation
Color correction filters restore color balance skewed by improper lighting, while color subtraction filters accentuate primary colors by removing specific colors related to light.
Contrast Manipulation
Diffusion or softening filters make images hazier or less sharp, colored filters enhance specific objects in black and white images (for example, yellow filters darken the sky but not clouds), and ultra contrast filters illuminate dark images to increase visibility of shadowy areas.
Neutral Density
Standard ND filters are gray filters that reduce light equally among colors. Graduated varieties target specific areas of images, such as the top or bottom.
Polarizer
Polarizing filters darken areas of images that are too light, an effect that software can't simulate accurately.
Ultraviolet Filter
UV filters decrease the fogginess ultraviolet light produces.
Special Effects
Certain filters can create stylized effects, such as sepia tones, motion blur and light-burst star patterns.
