Yesterday’s Topic: Camera Modes
White Balance is your camera’s attempt to make white be white. That’s really all it is. The camera knows if it can make white show as white, all the other colors will be accurate. White isn’t always white because not all light is created equal. For instance, a tungsten incandescent light bulb (the standard light bulb for the last 100 years, more or less) puts our light that is slightly more yellow/orange than the sun at noon. The measurement of this light is as a function of its temperature on a Kelvin scale, noted with a K.
Direct noon-day sunlight is the standard bearer of this scale for reference sake. It is pretty much at 5000K. Anything higher than this color temperature takes on a blue color and anything lower takes on an orange/yellow color. Back in the days of film you used to have to buy a roll based on the light you anticipated using. Most film was daylight balanced, around 5000-5500. Do you remember using that film indoors with tungsten light bulbs? Things took on a yellow color cast. And florescent lights? Greenish ick. This is also why flashes are set at 5500K, so as to be close to daylight, which is very handy when used as a Fill Flash (a post coming this month).
Digital cameras have the advantage of being able to adjust on the fly for the light coming in. But it can be a tricky business trying to guess the light source properly. Therefore, most cameras have the ability to manually change the white balance if desired. Here is a graphic representation of the various settings yoy might find and their relative value and place on the Kelvin scale.
Why is this important? When using a JPEG setting for file type, the white balance as the camera sees it is set when the file is compressed. No going back. If the camera picked the wrong white balance, the image may be too blue or orange or green. And that sucks. One way around this is to shoot in RAW mode because the white balance is not set, but instead written to a file that accompanies the RAW file. When viewed on a computer the information is re-read and applied, but if the white balance doesn’t match, you can simple tell the computer (either by a slider or by typing in the Kelvin temperature) what the white balance should be.
Try it yourself. Grab a white piece of paper and set your camera to daylight (5000K). Get the white piece of paper under an incandescent or fluorescent bulb and snap a shot. Even on the back panel LCD you will notice the color looks off. Off as in white is not white. Take the piece of paper out into the daylight (if you have it) and perform the same test. Bingo, white is now white. The color white is balanced.
If you don’t want to worry about White Balance, shoot in RAW and set the camera to Auto for the actual White Balance. Otherwise, if shooting in JPEG, be careful around harsh situations when the camera might get tripped up, such as:
- Moving from sun-filled to shade, especially with snow
- Going from indoors to out of doors
- Multiple light sources. In this case, you have to pick one and accept the others source(s) will show as exaggerated
- Large surface areas that are barely offwhite to start with
- High school basketball games
- Underwater (but this is a slightly different reason and why a number of point and shoots have a separate setting)
And check to make sure your camera is metering right. One other thing, you can set a custom white balance if you know the light will be a certain temperature for a certain period of time. This usually involves pointing the camera at something white and using a custom function, so you’ll need to look up how to set it in your manual. I know, homework. But it will help if you must shoot in JPEG and have some tricky light.
If you are looking for more in-depth info or a chance to get totally lost, check out Color Temperature on Wikipedia. It was also suggested to me there is a great explanation in the book Understanding Exposure so you might want to check that out as well.
Next Up: How To Take A Shot
31 Days To Better Photography is a series written by professional photographer Peter West Carey on The Carey Adventures.Com. The series is designed to unravel the mysteries of photography so you can take better pictures. Subscribe here to receive all the updates and bonus material. Your comments are always welcome.
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