Monday, April 12, 2010

White Balance

Do you remember your film pictures that you took at your cousin Grace's wedding reception about 22 years ago? You know, the ones that you used your camera's flash to light up faces with. They're the ones with white faces, but everything in the background is orange.

This is a white balance problem. White Balance has to do with the color of light coming into your camera. Daylight is very white, and florescent lights are green, and lightbulbs are orange, while outdoor shade is blue. Each of these colors of light must be dealt with or the pictures won't look quite right.

With Film, we either have to buy film specifically made for the color of light (daylight is the default), or we can counter it with filters on the front of the lens--blue filter counters orange light, pink counters green. Fortunately, in the digital world our cameras can adjust to the light without physical filters.

Unfortunately, your camera's default setting is "Automatic". This usually renders skin tones cooler than I prefer. Look for the White Balance setting on your camera, sometimes just WB. This adjustment alone will make your pictures look better immediately.

For this image, I had some trouble. There were regular old G.E. incandescent (tungsten) lightbulbs lighting the back of the shop to camera left, and large windows to camera right. The sun was not shining directly in the windows, so the light coming in is coming from the blue sky, which means it's very blue light.

So, this would be a very mixed up set up for white balance. I solved the problem by "gelling" my flash. This means I put a gel, a colored piece of transparent plastic, on my flash to match the color of the lightbulbs. This still doesn't solve the blue light from the window problem, though.

When using a flash, shutter speed controls how much ambient light is allowed to affect the exposure. Faster speed, less ambient light. The flash is fast, so it keeps up with a fast shutter speed without trouble.

The result is that the light making the exposure is almost all from the flash. there's a little bit coming from the lamp above the bench, but only because we're looking almost right at the bulb itself.

Besides the gel, I also put a diffusion dome on the flash, and shot it through my Zumbrella (though you can get the same one at a better value here). The flash is to camera right, triggered with the Nikon CLS system (that's the real reason I use Nikon).

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