Many photographers use the manual exposure settings on their cameras, aperture, shutter speed, ISO and shoot RAW. However, one of the few double edged advantages of shooting RAW is that your camera’s white balance setting will most likely take permanent refuge on autoWB
The logic that backs sticking with autoWB is essentially that white balance in RAW files can be changed to extremes in post production in the form of a slider in LightRoom.
Some photographers may work forever with autoWB and will simply adjust white balance to taste later. However, white balance can become infinitely more useful to you as a photographer if you can understand what it is actually doing.
White Balance is your camera’s way of compensating for the changes in the temperature (warm or cool) of light in a given scene. The color temperature is measured in Degrees Kelvin (K, for short). Throughout the day, the color temperature of daylight changes from dawn until dusk. The morning sunrise has a very warm, yellow/red/orange color. Midday is characterized by a very blue color and dusk returns to the warm red and yellow colors again.
So throughout the day the color temperatures oscillate between warm and cool; dawn-midday-dusk and everything in between. Coincidentally, there are a number of man-made light sources that fit right in with the color temperatures in nature. A camera’s white balance settings exist in order to compensate for these changes in color temperature and render a neutral white in the corresponding photographs, hence the name white balance.
The reason that white balance is such an odd concept to some boils down to how the human eye works. Last week I mentioned a little bit about how your brain filters out things that are not readily important, this is for survival. Your eyes automatically adjust to different color temperatures and lighting within different rooms because a long time ago you were more preoccupied trying to not get eaten. In reality, this is a great thing to have in your arsenal of characteristics. I’m pretty sure that if my eyes didn’t automatically adjust to the lights in a room I would get a headache very quickly.
White balance on a camera works in auto mode just the same way that our eyes do, and that’s great, but there’s no learning involved in that, there’s no progress to be made. What’s important here is that a camera can show you what the color temperature of the lights in a room are and your eyes cannot. You cannot readily see the color cast of a set of tungsten lights because your brain cuts down the effect, a camera does not.
Well…So who cares if your camera can see things your eyes can’t, what’s the point of learning about color temperature?
It’s important because you can use the concepts behind color temperature and white balance to create a photograph in the camera that is more closely tailored to the vision in your head. What is perhaps even more important is that you can use different white balance presets in combination with colored gels on any artificial lighting you may have in order to completely change the look and feel of a scene on several different levels and match artificial lighting with ambient lighting. How do you think a lot of movies have really nicely lit interiors from only a few lamps? Well, they have artificial lighting somewhere off-screen that is balanced with the same color temperature as the lamps.
First we’ll look at a white balance chart:
The chart above is a rough outline providing the color temperature values, in degrees Kelvin, of many different types of light sources. 10000K-15000K at the top of the chart is really really blue and 1000K-2000K is really really red.
The next thing to look at now that we have a rough idea of what color temperatures correspond to a given light source is a camera’s selection of white balance settings.
To avoid confusion, please note that a camera’s white balance setting, cloudy for instance, DOES NOT MEAN that it is the same color temperature of a cloudy sky (blue), it is exactly the opposite. White balance is meant to balance with a given color temperature so that they will, when used together, cancel each other out and create a neutral white.
Here is chart I’ve created to illustrate how white balance works with color temperature.
I remember this concept taking what felt like forever and a day to grasp a few years ago. Degrees Kelvin are always the same across the board, 6500K is really blue, 3200K is more yellow/red. The numbers in degrees Kelvin are the same in the white balance settings on the camera, the camera just adds the opposite of the Kelvin value to the image to compensate for too much blue or too much yellow.
If you’re using flashes, such as a Canon Speedlight 580EX II or Nikon SB800, or even a third party flash (my personal favorite, YN560-II) then you can use gels to change the color temperature of the flash output. Gels are little pieces of plastic, almost like cellophane, that come in many different colors, most often color temperature orange (CTO) and color temperature blue (CTB). CTO and CTB are the closest thing there is to a white balance for your flash. There really is no industry standard way of attaching gels to flashes yet, *cough* MagMod *cough*, although I am currently using Velcro on the sides of my flashes and on the gels themselves.
It takes a bit of setup time to create this type of system but it is ultimately worth doing if you have not used gels before.
Gels are excellent because they allow you to balance artificial light with ambient light. For instance, if I have a tungsten or incandescent lightbulb that sits around 3200K, my flash is daylight balanced at 5500K, I can use a CTO gel to warm up my flash to 3200K. Then I can use the incandescent/tungsten white balance setting to balance both light sources to white. Before, if I had not gelled my flash and used the correct white balance, whatever was lit by my tungsten lights would be white and whatever was lit by my flash would look extremely blue. It’s a very common lighting scenario to run into and it is overcome by the use of gels on your flash.
Or you could just dial down your ambient exposure with your shutterspeed and put the flash on the camera’s hotshoe with no modifiers like some sort of freak and take pictures like grandma does with her point and shoot at your sister’s third birthday party. Those always look good don’t they? No, no they don’t.
I hope this explains some things for you, leave a comment if you have any questions!