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Old Dec 16, 2003, 12:07 PM   #1
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Default How does auto white balance work?

Many digital cameras have auto white balance as well as several preset values and a manual setting. Usually, the manual setting is acheived by selecting a piece of paper or something else that you want to appear white, fill the frame with it (doesn't have to be in focus) and hit the shutter release.

My question is how does the camera do this automatically. How does it know what should be white? My Minolta S414 doesn't always get it right and I have to use one of the presets, usually tungsten.
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Old Dec 16, 2003, 1:29 PM   #2
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The simplest automatic white balance mechanisms look for the brightest point in the scene and assume it is white and adjust accoridingly. Better systems analyze the scene and perform a complex analysis of many different areas of the image based on a complex algorythm. The fact that the automatic white balance doesn't always get it right is the reason that you have options to control white balance.

Just like automatic exposure meters built into your camera, certain assumptions are made and those assumptions are not always correct.

This is when the photographer needs to make the necessary adjustments to create the image that he/she sees in his mind.

Greetings from Medford, btw
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Old Dec 16, 2003, 1:56 PM   #3
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Auto white balance can also depend on what types of metering you have available on your camera. Check your manaual
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