Most professional video cameras have a white balance memory switch. The A and B positions allow a videographer to memorize white balance settings under two different lighting conditions and, providing that you remember which letter goes with which location, flip instantly back and forth between them without taking time to rebalance. This is especially useful when you are following action that takes you from sun to shade or indoors and out.
But what about the switch’s third position? Often labeled Preset, this setting totally disengages the white balance control and makes a video camera act just like a film camera. The only color balance compensation comes from the filters behind the lens. Set the switch to Preset and you’re ready to shoot under 3200K lights with the Number 1 filter or in direct sunlight with filters 2, 3, & 4.
This can be handy if you grab the camera for a hurry-up shot and absolutely don’t have time to do a white-balance, but it is even more useful when shooting under extreme lighting conditions. When you’re shooting +18db at a night-time street scene and the light sources include sodium vapor street lights, automobile headlamps, flashlights, and emergency vehicle worklights, electing to go with Preset is quicker and often safer than trying to find something white that is illuminated by a representative mix of the available light.
