R30 - Camera Work - White Balance

White balance - what we perceive as colour is actually light of a specific wavelength entering our eyes. The colour white reflects all wavelength of light so if you shine purple light on a white sheet of paper it'll look purple and same with other colours. This is important because in different conditions and lighting situations different colours of light dominate. For example shady light is a little bit blue, whereas sunny light has a yellow tint and indoor incandescent is orange.
Which is why a white piece of paper, for example, in those conditions would look either blue, yellow or orange.
A camera can only record the actual wavelengths of light hitting its sensor

White balance is how your camera compensates for those small colour shifts
If you're in a shady/ blue lighting by changing the setting to shady which adds warmth and amber tones which gets rid of the blueness.
If you're in a sunny area the camera will add blue shady tones to it so that the white stays white.

Sometimes you may want to emphasise certain colours in your image over other colours. So you can change your camera settings to certain white balances to alter and manipulate your image to make it look better. For example if you're shooting an image of glacier as mentioned in the video then adding blue tones helps to bring out the image more.

Tip: changing white balance in the field while shooting rather than changing it later is better because when you change the colours you see you'll often see the scene in a different way.