Wednesday, January 17, 2007
June 2006 HelpLine
* Do You Need White Balance With RAW?
* Protective Filters
* Reboot For Performance
Do You Need White Balance With RAW?
Q) Since I got my digital SLR, I've really enjoyed the flexibility that comes with shooting RAW. While this "digital negative" has been fun, I do wonder about bothering with setting white balance. Since I can adjust the white balance to whatever I want when converting the RAW file, I've just been ignoring the white-balance setting. Am I missing something here?
A) Before I get into your white balance question, I'd like to respond to the term "digital negative." It's true that this is a convenient term and has been made even more popular since the introduction of Adobe's DNG format. But to try to use it as an analogy between film-based photography and sensor-based photography is a little misplaced. A more closely matched term would be "latent image" rather than "negative." Just like the latent image on exposed but unprocessed film, the RAW file is invisible until it's processed in some manner.
The analogy goes even further: There are different processing methods to "develop" the "film" or RAW image (you can't reprocess a negative, though you can print it differently). Just as a photographer might develop black-and-white film in different ways with various developing chemicals, a photographer might "develop" the digital latent image using Adobe Camera Raw, Raw Shooter, Capture One or the RAW image processor that came with the camera, and each one will result in a slightly different version of that RAW file.
Now, on to white balance. It's true that the white-balance setting can be adjusted during RAW processing. This is because the white-balance camera setting is just a bit of metadata stored in the RAW file. It doesn't affect the sensor data until you start processing the file.
While you can ignore white balance during shooting, you'll only delay your adjustment. There are several problems to this approach:
1. You'll need to do a basic white-balance correction for all of a group's shots before you get to any other processing adjustments or else colors will be difficult to match. This adds more work to your processing.
2. If the white balance is far off, your initial image viewing might be distracting—you might concentrate on the image's color problems rather than looking at other aspects. This can be especially tricky when you're dealing with a large number of images.
3. If you're shooting with auto white balance, and your composition changes (say, from zooming in or out on your subject), you can find your white balance changes from shot to shot. Then you'll have to try to match them, plus you won't know which one is more accurate.
4. On a more philosophical note, ignoring white balance can lead photographers to start ignoring other camera settings. I've heard some say that they don't have to worry about exposure or they don't have to bracket anymore because of the miracle of RAW format. Though it's true that you may "get an image" from a marginally exposed shot with RAW, there's no substitute for good exposure.
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