Just setting the color temp to AWB and forgetting it is not always a wise solution. RAW doesn't save all the gamuts of color that always completely represent the true colors.
Before you give advice you really should be positive on your facts.
Yes, you should. Your
'facts' are wrong. A RAW file does not have a color temperature applied to the data
(only the metadata). RAW image data contains the readouts from individual pixels - each pixel is a monochromatic sensor (it counts photons regardless of their wavelength), with color data coming from the overlying filter in the Bayer mask - but even though that limits the photons counted to those of a particular part of the visible light spectrum, even that 'color' is artificial - pseudocolor, if you will, based on the RAW conversion software knowing which color (R/G/B) mask was over that particular pixel). Thus, the setting you choose on your camera for the white balance has no effect whatsoever
on the image data in the RAW file.
It's true that at high ISO, dynamic range is compressed and the ability of the camera to accurately capture the full color gamut is compromised - but for a RAW image that results from the lighting conditions and the ISO setting, not the irrelevant WB setting on the camera.
If your white balance setting is affecting your RAW images, it's an indirect effect that could be called operator error (if not error, then a lack of understanding). Although the WB setting does not affect the RAW image data, it does
affect the JPG conversion. But wait, you say, "I shoot RAW!" Even if you're shooting RAW, a JPG preview image is embedded into the RAW file, and that JPG image, converted in-camera based on your settings (including WB, picture style, etc.) is what's displayed on your camera's LCD, and also what's used to generate the histogram displayed on your camera's LCD. So, if you alter your exposure settings based on that preview image/histogram on-camera, that change in exposure will affect your RAW file image data.
For example, a large red object under mixed but mostly tungsten light, with AWB set on-camera, may not saturate the red channel of your reduced bit-depth JPG preview/histogram, even if the 'real' red channel is actually saturated (real meaning the RAW data from the pixels under the red filters in the Bayer mask). So, you may feel comfortable bumping your exposure up a little more (ETTR), and end up significantly clipping the red channel in the RAW image. But that wasn't the WB setting affecting the RAW file, that was you changing the exposure. This is a situation where knowing how your equipment works, and it's limitations, can help you avoid problems.Skitron
, you are (mostly) correct. The RAW file is the mostly
'as is' data from the sensor. The sensor itself is analog, and the analog data (photons stored as an electirc charge in each pixel well) must be converted to digital information - some minimal processing is also applied as part of that process (differs by manufacturer and model, but they don't disclose that information). Data for each pixel are stored separately in the RAW file (and later must be demosaiced, i.e. the Bayer color mask of red-green-blue filters over the pixels must be interpolated to merge the color channels). The settings selected during shooting (white balance, picture style, ALO, etc.) are recorded as metadata in the RAW file, but do not affect the image data (one exception to that is highlight tone priority, which does affect the RAW file). Depending on the software you use on your computer, some or all of those parameters may be applied as defaults to the RAW file during conversion/viewing - Canon's DPP applies Picture Style, ALO, etc.; 3rd party RAW converters (Adobe ACR, Lightroom, Aperture/iPhoto, etc.) read and apply the WB but little else, and in some cases not even the full WB data (for example, with WB set to AWB or Flash, if you use a Canon Speedlite the color temperature of the flash is reported by the flash to the camera and added to the metadata; if the WB was set to Flash, DPP will use the 'custom' color temperature of the light, whereas 3rd party software will just use the Flash default, e.g. 6000K). But regardless, you can change the WB setting in the RAW file with no penalty to image quality, since you're just changing metadata.
Hope that helps...