Originally posted by lakeshore When using your camera for general outdoor photography in JPEG mode, do you use the AWB setting for the most part or do you routinely alter it to Daylight, Shade or other?
AWB generally does a good job, though if one is shooting JPEG an improper white balance may be difficult to undo without artifact in post-process.
Originally posted by lakeshore Does AWB tend to skew the colours in any particular way, such make them too warm?
No...my experience has been that when things go wrong with AWB, just how it goes wrong is difficult to predict.
Originally posted by lakeshore Under what sort of conditions do you adjust the setting, other than for artificial indoor lighting?
That is a loaded question. The general settings (daylight, shade, tungsten) are, well, general. A more specific approach is to adjust the white balance to match the incident light. On a Pentax dSLR this is done using an 18% gray card or standard white card reference and the adjustment feature of manual white balance. The general procedure goes something like this:
- Go to the manual white balance adjustment feature of your camera. How this is done varies between models. Your user manual is a good resource here.
- Place the gray (or white) card in the same light as your subject and oriented towards the camera
- Frame the card in the viewfinder and press the shutter button to take an exposure of the card. The camera will display the image rendered with the existing WB settings and the option to accept/reject that image as appropriate for adjustment as well as cancel the operation.
- Accept the image and the camera will display the image again with the adjustments applied
- The camera may also provide additional adjust to provide additional fine adjustment. Be aware that the rear LCD may not reflect the rendering of ones editing environment.
- Exit out from the manual WB screen and take a test image of your subject and evaluate for unwanted tints
- Repeat steps 1-6 as needed until satisfied
- Shoot at will!
Your camera may also support additional features to support manual WB. The user manual should provide clues on how to use them, but may not be as helpful as one might desire.
An important thing to remember is that it may not be possible to apply a white balance setting that will account for multiple light sources or light sources that do not approximate black body incandescence.* For those cases a shooting RAW processing against a custom color profile might be more appropriate (a whole 'nuther topic).
Finally...There is a strong case for simply shooting RAW with AWB and including at least one capture with a gray or white card or ColorChecker. That one frame may provide a reference in post-processing and/or a reference for in-camera RAW --> JPEG/TIFF.
Steve
* Black body emission (aka incandescence) at various absolute temperatures (degrees Kelvin) is the basis for the concept of color temperature and the practice of white balance adjustment.