Originally Posted by TJPhotoGuy
That's weird because I tried that years ago using that same technique before and it didn't work - the colors come out wrong. I asked around and was told that when shooting raw, white balance settings don't apply. In fact, right n the manual for the 20d, it says if you're shooting RAW, that the white balance settings don't even apply, and you have to fix it in post-production software.
There is a lot the manual doesn't say. When shooting RAW, here's what happens:
1. You shoot the Photo.
2. At this point all the image data is in the camera's memory buffer. This all happens in a split second.
3. Now the camera creates 1500x1000 JPG image in its memory buffer and it displays this on the LCD. It applies the camera parameters and WB (including CWB if any) to the JPG. So what you see in the preview on the LCD is the White balanced image and the results of any parameter settings.
4. It writes the RAW data to the card. Imbedded in the RAW data is the above JPG file (which has been corrected as indicated above).
With the right software, you can even extract that JPG image later for fast preview. I use the imbedded JPGs for showing a slide show of the shots shown during a wedding (for example), during the reception because they can be extracted so quickly (about 90 seconds for a 1gb full CF card).
Now as far as the WB settings being applied to the RAW image, that is mostly true. They are not. The RAW image has all the data that was in the scene that the camera could capture. However, when you first preview the RAW image in outside programs, some of them will give you the preview based on the imbedded JPG while others will do a quick post process to generate a JPG. This may or may not use the WB settings. Each piece of software is different.