If someone asked me what an inspiring digital wedding photographer should master - along with composition and framing white balance would be on that list. (And if you aren't shooting manually by now, this is your cheerleader saying, "you can do it!")
According to the internet: White balance (WB) is the process of removing unrealistic color casts, so that objects which appear white in person are rendered white in your photo. Proper camera white balance has to take into account the "color temperature" of a light source, which refers to the relative warmth or coolness of white light.
Basically your white balance is the tool we use to make the color in photos look the way we want them to. We want them to look as realistic as possible IN CAMERA so that editing time is cut way down. Yes, mastering your white balance means you improve as a photographer because every image you take will be closer to the final product. Improving rocks!
So how do we manually set our White Balance?
We shoot in Kelvins.
I can honestly tell you on my 6D I never had to manually set the white balance. It was excellent at reading my mind. But with the 5DMarkiii I have to do a lot more to achieve the tonality I want in photographs. (But obviously the 5D is a monster in other regards).
There are a couple of ways you can manually set the 5DMarkiii's white balance. The way I do it is by pressing the video button (the one at the top right corner of your LCD display), and then WHILE you’re in video mode, press your “WB” button, select “K” for Kelvins, and then adjust the degrees according to how warm or cool you want your settings to be. The Live View mode allows you to see how the changing settings will affect your image will turn out without having to take a test shot, so it’s quick and easy! The other method is by finding “White Balance” under your “Shoot” menu.
Friends, having more control over your white balance WILL COMPLETELY TRANSFORM YOUR IMAGES! You'll have so much more control and I promise you will be impressed with your results!
Here are two examples of BEFORE (Auto White Balance) and AFTER (Custom White Balance)