This is a good exercise if you have never tried it. Take your camera, set it to RAW. Pick out a simple texture, such as a brick wall and take three images with different WB settings:
1. Kelvin @3100 (or Flourescent)
2. Kelvin @10000 (or Sunlight)
3. AWB.Open the files in Adobe Raw. Notice that the new Adobe RAW preserves the WB and that you get the “hot” and “cold” temperatures. This is a little misleading however, because once you move the WB sliders to match the AWB….. …… we can see that the images temperature (and appearance) are the same. What these means is that WB for RAW only determines the starting point of the slider, however it can be easily adjusted and the original information is still there. The Previews we see on the back of the camera are JPEG thumbnails, and do not represent an absolute setting of the RAW file.
What I am saying is this: if you are shooting in RAW, it is going to take much more time to custom white balance in every new shooting situation (which you might tweak anyway) than to tweak in Camera RAW (by moving a slider). You can also batch your WB in many different ways (as shown in the Photoshop DVD).
WB for JPEGs is a different matter. All images start as RAW files and as they are converted to JPEGs, anywhere from 70-90% of the original data is thrown out and irrecoverable, and you will not be able to “save” the images with this simple slider move. (try it out if you haven’t) ~ (Although using this technique to save JPEG color balance in RAW is one of the easiest ways to do it if you are in a jam, just not recommended if you can help it).
If you are shooting Jpeg only, then yes, it makes good sense to WB when you are unsure, Im more of a Kelvin WB guy myself, especially for videos, because you can just dial it in exactly and see on the preview.
Additionally, “Picture Styles” which determine different levels of saturation, sharpness, etc, only apply to JPEGs. You can tweak them all you want and see the adjustments on the back of your camera, but if you are shooting in RAW, these changes will not take place on the RAW files…you are essentially wasting your time unless you render them as JPEGS as well.