Everyday we’re surrounded by light. Nature and the sun, electricity and lights. Tungsten, florescent, incandescent, etc. We’re around light so much, that we don’t realize how complex it is, and furthermore, we don’t realize how well our brain helps our eyes adjust and adapt to different types of lighting.
In photography we talk a lot about how to use light, how to control the way it falls on a subject, how to compensate in-camera for bright or low lighting, and how the camera sees light.
Our eyes and brains are so adept at adapting to light, that we don’t even realize that every different type of light has it’s own temperature. Items we observe under different types of light with our own eyes will always look the same, but when we photograph the same items under the same lighting conditions with our cameras, things start to look very different.
What is AWB? (Auto White Balance)
The digital camera’s sensor doesn’t read or adapt to light as well as our brain or eyes. Because of this, camera manufacturers have created a way for our cameras to adjust to light using the AWB(Auto White Balance) setting.
This is the most basic way to try to maintain the same neutral lighting settings within your camera under any lighting situation.
But what does AWB really do? It actually just automatically adjusts your sensor along the Kelvin scale to find the most neutral lighting setting.
(2700K photographed just after Twilight, IS0: 100 f/2.8 2″ sec, Canon 5D mkiii)
What is the Kelvin Scale?
dictionary.com defines the Kelvin scale as, “an absolute scale of temperature”. In its most basic form, it is a way for us to measure temperature.
I shoot Canon, so I’ll use my camera as an example. Canon EOS Digital SLRs adjust white balance over a range of roughly 3000 to 7000 degrees Kelvin, when set to AWB. (Eduardo Angel, Canon, Understanding Kelvin White Balance In Changing Lighting Conditions, Canon Digital Learning Center, http://www.learn.usa.canon.com/resources/articles/2013/kelvin_white_balance.shtml) Meaning, when set to AWB, your camera goes up and down the Kelvin scale automatically, depending on the temperature of light that your camera’s sensor is detecting.
Even more, not only do our cameras have an AWB setting, we’re also provided with several WB presets. These presets can sometimes be found on the camera’s “mode dial” or can be accessed by pressing the camera’s “WB” (White Balance) button, and are normally displayed on the camera’s upper LCD panel. Usually illustrated by icons, the presets are: Auto, Daylight, Shade, Cloudy, Tungsten, White Fluorescent, Flash, Custom, & Color Temperature (Kelvin).
The last two options, Custom and Color Temperature are a more manual way of controlling temperature. Camera WB presets are meant to be general setting options to quickly access for a variety of lighting situations.
This is not an absolute Kelvin scale but rather meant to act as a reference guide.
How to Shoot Using Kelvin
If you want to have total control over your WB in-camera, best practice would be to use the Color Temperature setting (illustrated by the “K” symbol). This allows you to choose a specific Kelvin temperature for whatever setting you may be photographing in.
Once you’ve set your WB to K (Color Temperature), you’re then given the option to choose a color temperature between 1500K-7000K (depending on camera make and model).
Trevor Dayley over at fstoppers.com gives a great tip on becoming comfortable using your Kelvin WB setting: “One little trick that works quite well when you are learning how to use your white balance settings is to turn your camera’s live view mode on. In this mode, often used for video, you will be able to push the WB button and click through the WB settings or dial in your Kelvin temperature all while seeing the changes happen in real time in your camera. This is a great way to practice.” (Trevor Dayley, How To Get Correct White Balance In Camera, FStoppers, http://fstoppers.com/learn-to-shoot-proper-white-balance-using-kelvin-temps)
Something of importance to note is that the Kelvin Scale only measures in amber and blue. It does not take into consideration magenta or green. Once you become comfortable adjusting your Kelvin, you may also want to take a stab at the White Balance Shift options available in-camera as well. Shifting your WB to either magenta or green while simultaneously adjusting your Kelvin will ensure the perfect WB in any photo, in any lighting situation.