Although it's usual for photographers to use filters to protect their lenses from scratches, thumbprints, and dust, the real benefit lies in the way filters improve images and, in some instances, achieve effects that even the best photo editing suites cannot replicate. There are many different types of lens filters, each for a specific purpose. Filters attach in one of two ways. The most common are circular filters that directly screw onto the lens. The second method is to use a filter holder that accepts universal type rectangular filters. This is useful if you use multiple filters to obtain different effects.
DSLR lens filters fall into three general categories and are available from many popular brands. Names you'll often see include Tiffen, Hoya, Heliopan, and Canon filters. Some primarily protect lenses against dirt, dust, or moisture, while others change the properties of light as seen by camera sensors, while yet others create special effects. Common filters used by photographers include:
A photo filter or video filter must be the right size to fit the thread on the front of the lens. The diameter is stamped or printed on the lens body, usually toward the front. Because lens sizes vary, it's common to have filter kits for each lens.
Although it's possible to use several circular camera lens filters, one on top the other, this isn't a good idea because the multiple layers of glass may affect image quality, and, if the filters extend too far, they may interfere with the picture when you're using a wide-angle lens. When several filters are needed, consider using rectangular filters mounted in a separate holder. These filters are thinner and made of plastic, gelatin, or resin, and cause less distortion.
Some filters are adjustable. A polarizing filter turns to obtain the desired effect, while an adjustable neutral density filter darkens. Colored filters change the hue, correct for color temperature, increase the warmth, and reduce the harshness of bright lights.
Protect your camera lenses and improve your photographs with help from B&H Photo and Video's selection of neutral density, protective, and polarizing filters.