How to Choose Camera Filters

Determine the lens size. Remove the lens cap from the lens and examine it. The cap will have a number stamped on the reverse side, indicating the size of the lens. This size is normally anywhere from 50 to 80 mm.

Determine the type of filter that you need. There are hundreds of filters available, and each has a specific purpose. The four most commonly used filters are UV filters, polarizing filters, neutral-density filters and warming filters.

Select a UV filter if you are looking to protect your lens without altering the image. This type of filter is useful if you are shooting outdoors or in potentially damaging environments.

Select a polarizing filter if you are looking to tone down glare. Polarizing filters consist of two pieces--a stationary piece that fits to the camera lens and a rotating piece that can be used to change the parallel filtering line orientation. This type of filter can minimize reflections from a surface such as glass or water and can reduce atmospheric haze and "orbs" produced from dust particles.

Select a neutral-density filter to reduce the amount of light entering the camera. This allows the photographer to use a slow shutter speed in a bright situation, which is useful for creating motion blur. Neutral density filters can also come in a graduated form, where the light is blocked on one side of the filter and allowed in on the other.

Select a warming filter to change the hue of the photograph. This changes the color temperature of the light entering the lens, enhancing tones and colors. Warming filters come in several varieties, with varying degrees of effect on an image. Although this technique can be imitated in Photoshop or by changing the white balance on the camera, some photographers prefer the simple step of adding or removing the filter.