- Many camera lenses are sensitive to haziness caused by sunlight. This can give your pictures a washed out look that is unappealing. However, an ultraviolet filter eliminates this haze by filtering out the ultraviolet light that creates the hazy, washed out look. UV filters are perfect for shots with lots of sunlight, such as in the mountains or in the desert. Digital cameras aren't as sensitive to UV light as film cameras but UV filters still help eliminate that washed out look.
- Keeping your camera aperture open longer lets you capture more aspects of the image but also exposes your film to more light. An ND filter helps reduce the total amount of light that hits the lens and the film. This gives photographers a chance to create longer exposures without ruining the film or flooding the image with overwhelming brightness. This lets a photographer capture motion he wouldn't have been able to with a shorter exposure time.
- Emphasizing the contrast in your photos colors helps the images stand out from each other more fully. Color filters help emphasize or de-emphasize certain colors in the spectrum. The color filter depends on the color of the lens. A blue filter would filter out light of the blue spectrum, bringing a higher contrast to yellow colors, red and orange colors. Color filters are rarely used since the dawn of digital photography; contrast can be controlled more precisely using digital design software. However, photographers using film may still use color filters.
- Infrared photography is the photography of the light spectrum that is opposite the UV spectrum. This type of photography creates pictures that differ vastly from UV spectrum pictures. IR filters eliminate all light but infrared light from your camera. These filters are generally not used on digital cameras as they are not designed to pick up infrared rays and will only result in a completely black photo. However, digital cameras can be modified to use an IR filter by purchasing and installing an IR sensor on your camera. This is not suggested unless you understand how to modify your cameras electronics.
- Graduated lenses are used to eliminate brightness in a photo. Reducing brightness helps eliminate the blurred look between the sky and the ground that can occur on unusually bright days. This makes your photo clearer and helps differentiate the objects in your photo. This is different from emphasizing contrast because it does not emphasize certain colors over others. It simply eliminates the bright "wash" of light that can occur on sunny days. These filters come in different strengths and reduce brightness by varying degrees.