If you had asked me a few years ago if I could tell the difference between a photo shot with Auto white balance and one with a specific setting, I would have laughed and said, “No way.” Auto white balance may have its problems, but I didn’t think it was that distinctive to immediately show up in a photograph.
I would have been wrong. While I can’t pick out Auto white balance every time it’s used, I see it frequently in the hundreds of students I work with in classes on the web and around the country—too frequently for it to be a coincidence.
Disadvantages Of Auto White Balance
Here’s the problem: Auto white balance typically gives colors that are neither as good as they should be, nor consistent from frame to frame. Auto white balance is designed to constantly change and adapt to different conditions.
The AWB image of this stream in Sedona, Arizona, definitely looks okay. But it’s not nearly as inviting a photo as the warmer image shot with Cloudy white balance. The rocks and white water of the AWB shot have a blue cast, plus this added blue dilutes the green of the trees in the background.
For example, it doesn’t know the difference between a change in light and a change in your zoom’s focal length. You can go from a wide-angle shot with one set of colors to a telephoto shot that changes the colors. This can be annoying when you have a series of pictures that are supposed to go together, such as your latest trip to a foreign city. Your subjects may have inconsistent color even though nothing changed except that you took a different picture.
The other problem is compromised color. It’s common for Auto white balance to leave a slight blue colorcast to the overall image, especially on cloudy days. This makes grays and other neutral tones bluish, makes the image look cooler than it should be and degrades the saturation of other colors. If you’re shooting sunrise or sunset, you’ll never get the best images from those subjects with Auto white balance.
What About RAW?
At this point, some people are thinking, “I shoot RAW, so this doesn’t matter. I can change the white balance whenever I want to in the computer.” Unfortunately, Auto white balance isn’t so simple.