Auto white balance is a useful tool, but can be limiting if it's the only white balance you use
By Rob Sheppard
With the popularity of digital cameras exploding, many photographers now know about white balance, yet this isn’t new technology. It began with video cameras nearly 50 years ago, when color television became common.
This same idea was adapted to digital cameras and is a tremendous help. With film, matching colors to a scene often required extensive filtration, and even then, you couldn't be sure. With digital, you can count on colors being accurate, especially since you can see them right away as you shoot. While the LCD monitor won't give completely accurate colors, it will give you enough of an idea of what's in the image file that you can judge if your white balance is doing the job.
It's interesting to note that at all major sporting events covered by the networks, they use their big video trucks with hundreds of thousands of dollars of technology, while the network camera people still use manual white balance; it's called "painting" or "shading" in the business. Do they know something we don't? Why not just use auto white balance? After all, auto white balance uses complex algorithms and internal camera processors to examine a scene and try to match the manual adjustment of white balance. Manufacturers have become very good at this, making auto white balance a valid tool. Still, many pros prefer selecting specific white balance settings for several reasons:
1. Auto white balance can shift as a lens is zoomed or the composition changed across a scene. This can make matching images more difficult when working with them later; this wasn't a problem with film, as film had one and only one "white balance" matched to a specific color of light.
2. Having a specific white balance makes colors more predictable. This is just like shooting a specific film; you know what the colors will look like.
3. The range of color temperatures balanced by a camera is generally greater manually than on automatic.
4. Scenes usually are completely cleaned up from overall color cast problems (some color casts, such as sunset colors, are supposed to be included).
5. Panoramas need consistent colors; auto white balance can change enough that time must be spent balancing different frames in the computer.
6. RAW workflow is more efficient because you chose a white balance specifically for the scene; each image from that scene will have a consistent color.