White Balance
Understanding digital white balance can help you avoid color casts created by your camera’s AWB, thereby improving your photos under a wider range of lighting conditions.
At its simplest – the reason we adjust white balance is to get the colors in your images as accurate as possible.
When learning photography it is important to be aware of the color of light. Through a process known as chromatic adaptation the human eye automatically adjusts to the color quality of light. When our eyes see an object such as a white wall or white piece of paper the brain automatically assigns it the value of white. Like our eyes, a digital camera needs to find a reference point which represents white. It will then calculate all the other colors based on this white point. For instance, if a halogen light illuminates a white wall, the wall will have a yellow cast in your photograph, when in fact it should be white. So if the camera knows the wall is supposed to be white, it will then determine all the other colors in the scene accordingly.
White balance is expressed in terms of color temperature. Low color temperature implies warmer (more yellow/red) light while high color temperature implies a colder (more blue) light.
AWB (automatic white balance) is the default setting and the one you could use most of the time. Daylight, shade, cloud, flash and tungsten are all fixed settings that you can use under the appropriate lighting conditions. Have a look at the chart to understand what they do. Basically they are like the old filters that users of film would screw onto the front of their lenses to compensate for different color temperatures. The advantage of using these fixed settings as opposed to the AWB is for more consistent and accurate color.
Tip: If you photograph a sunset using the AWB setting, the camera will decrease the intensity of the oranges and reds in the photograph. Set the white balance on the sun icon (daylight) to retain the color of sunsets or use the shade icon (shady) to warm up the colors and intensify the reds even more.
Tip: Try photographing a night landscape just after dusk with different white balance settings. A daylight setting at night will give the photo warm tones if most of your light source comes from tungsten lights. For street lights and other common scenic light sources, try a tungsten or fluorescent setting for a more natural look to the light. Mixed light sources (a sunset sky with fluorescent lights in the foreground, for example) can give some really interesting looks to your shot.