Filters

BY SUZANNE WILLIAMS

Lens filters are used to take your image from just "okay" to excellent. There are many types of filters out there for many purposes, but I have four that I use the most: neutral density, split neutral density, polarizing, and infrared.

Filters come in two types - circular or square. I have always used circular filters. However, both achieve excellent results. Do some research to find out which shape will work best for your camera and your style of photography. Be sure before purchasing to consider the size of your lens, and always shop around for the best price and product. New filters are great, but I have found top-of-the-line used filters at my local camera store for a much cheaper price. Also, keep in mind that filters are glass and so they are breakable. You will want some type of padded camera bag to store them in.


NEUTRAL DENSITY

Neutral density filters lower the intensity of the surrounding light. They come in a range of strengths, typically 2x, 4x, or 8x. The higher the strength, the more light it removes. The strength you need depends on what you are using it for. Most commonly, I am trying to slow down running water. For this I use an 8x strength filter.

Notice I said "slow down". Neutral density filters enable you to use a longer shutter speed in bright light. The longer shutter speed allows the movement of your subject to appear blurred, as in the water image above. But always remember that longer shutter speeds require some form of steady support for your camera.


POLARIZING

I wanted to introduce the polarizing filter at this point because I often use it in conjunction with a neutral density filter, especially in photographs with water. Polarizing filters do a number of things. They remove the glare of sunlight. They also magnify colors, especially green tones. They enhance contrast in the sky. They remove reflections from water. (If you want to know how these filters work, Wikipedia has an excellent article.) For this reason I often combine a neutral density filter and a polarizing filter. But remember, the additional weight of a polarizing filter reduces the light even more. This will require an even greater adjustment to your shutter speed.

Part of the greatest effect of a polarizing filter comes from knowing when to use it. When the light is at certain angles in the sky, you will see little if any effect at all. It can be a detriment at these times, so I caution against overuse. Always be sure you truly need one before you use it. Otherwise, a good photograph can be lost.


SPLIT NEUTRAL DENSITY

Split neutral density filters, like neutral density filters, come in a range of strengths. The difference between them is the lower half of a split filter is clear. The advantage of this comes into effect with images where you have a lot of sky. They prevent "white sky syndrome". This happens when the range of light in a photograph, such as the mountain image above, is too great for a camera. If you were to meter for the darker mountains, your sky detail would be lost. If you meter for the sky, your mountains appear too dark. A split neutral density filter counters this. It allows less light into the camera on the upper portion of the image and more at the bottom, thus evening out the light in more difficult scenes.


INFRARED

Truthfully, infrared filters are more for entertainment than anything else. I enjoy using them because the results can be so startling. They work by filtering out all but the infrared light spectrum. They work best in the brightest sunlight, in fact, in scenes where ordinarily you wouldn't take a picture. This, of course, means that you will have really long shutter speeds. A tripod is required. It also means your subject needs to either be still or you will have a blurred effect. In the bald cypress tree picture above, the longer shutter speed had a nice effect on the water of the lake.

Taking infrared photographs alters your visual perception. Green leaves become white, whereas skies and water turn almost black. They work great for capturing the shape of limbs and trees or in architecture images. Depending on your camera, the initial resulting image is a shade of red or pink. I always prefer to convert the photograph to black and white.

These four filters help to compensate for the natural deficiencies all cameras have. They also cause you to learn more because you must think harder about adjustments to aperture, ISO, or shutter speed. In the end, with their use you will find yourself better capturing and greater enhancing your photographs. The viewer in return will more enjoy your results.


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Suzanne Williams Photography
Florida, USA

Suzanne Williams is a native Floridian, wife, and mother, with a penchant for spelling anything, who happens to love photography.