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| Photo by Guy Tal |
| Slot Canyon, near Zion National Park, UT. Click the photo to see this shot in four kinds of WB. |
Budding photographers usually get the same sage advice: Learn to use your manual controls -- shutter speed, aperture, focus, and meter pattern -- for the desired effect in each individual scene. Still, most photographers leave one critical setting on automatic: white balance. That's a mistake, because this control can have a profound effect on your photos -- even monochrome images.
To understand white balance, first consider that light comes in different colors. A candle or wood flame will cast shades of warm orange and amber; fluorescent lights tend toward a cooler, sometimes even blue, tint. A consistent shift in color throughout the whole image is called a color cast.
The standard measure for the color of a light source is color temperature, measured in degrees Kelvin. It may seem confusing, but lower readings are associated with warmer tones while higher readings indicate cooler ones.
Without a camera, our brains adjust white balance. If we know something to be white, we'll perceive it as white even when the color of the light changes. But a camera needs to be told what to do.
The white balance (WB) control on a digital camera allows you to compensate for differences in ambient color temperature. It adjusts the balance of red, green, and blue in the image so that neutral tones (white and gray) remain neutral, whether you're in a hall lit by Tiki torches or in the depths of a shaded forest -- or even underwater, where overall color can be very cool and blue.
Digital cameras offer WB presets for specific conditions (Daylight, Cloudy, Tungsten, etc.), as well as an Auto mode, which tries to determine and compensate for color temperature. For more accurate balancing, most DSLRs offer a custom setting, which lets you take a reference shot to base the correction on. Some cameras and most RAW converters allow even more control by letting you directly set the color temperature in degrees Kelvin.
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| Photo by Guy Tal |
| Pond Lilies, Uinta Mountains, UT. Click the photo to see this shot in two different WB controls. |
In nature photography we generally rely on the sun as our primary light source. Color temperature outdoors changes throughout the day and may be affected by such factors as the position of the sun, the presence of clouds or haze, whether you're in direct light or shade, and whether the light is reflected off something that absorbs parts of the spectrum.
The good news is that color accuracy is not as critical in nature photography as it may be for some types of commercial work in which, for example, a product's image must match its color exactly or a bride's dress must be perfectly white.
On a given day, color temperature may range from very low (yellow/orange) at sunrise, through neutral around midday, and up to very high (blue) shortly after sunset. Even at the same time of day, it may vary widely between direct sunlight and open shade, reflecting the blue sky.
At a given WB preset, these differences will produce casts in light that do not match your preset. For instance, setting your camera to Tungsten and photographing a sunlit scene will result in a deep blue cast, since the camera assumes the color temperature is much lower than it really is -- yellowish -- and counters it by adding blue. Even with a neutral setting such as Daylight, you'll get color casts under heavy cloud cover, in deep shade, or at sunrise or sunset.
Keep reading for four tips on using WB to your advantage in nature shots.
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