I have been shooting RAW with auto white balance thinking that it made no difference since I could post process the errors out.
This is WRONG
Shoot some pictures under strange lights, mercury vapor or florescent at higher ISO and you will see a big difference. With auto white balance the shadows will have a green cast to them. There is no way to remove the green cast without totally messing up the flesh tones. I have had some success exporting TIFF files and working with them in Photoshop using the gamma correction on the green channel. Nothing works as well as doing a custom white balance before shooting.
The camera does something more that just tag the file with balance info. Now I am a happy man with no more green shadows.
This is WRONG
Shoot some pictures under strange lights, mercury vapor or florescent at higher ISO and you will see a big difference. With auto white balance the shadows will have a green cast to them. There is no way to remove the green cast without totally messing up the flesh tones. I have had some success exporting TIFF files and working with them in Photoshop using the gamma correction on the green channel. Nothing works as well as doing a custom white balance before shooting.
The camera does something more that just tag the file with balance info. Now I am a happy man with no more green shadows.