Manual / Custom
A method of setting white balance according to the shooting conditions present. Typically a target needs to be shot, which is then used as a reference point for subsequent images. Some manufacturers use the terms ‘custom' and ‘manual' for describing manual selection over the colour temperate scale (in Degrees Kelvin).
The automated white balance setting allows the camera to judge shooting conditions and adjust white balance accordingly. This is useful if shooting in constantly varying conditions, but it's not always entirely accurate.
A unit of temperature relative to absolute zero, named after physicist William Thomson, 1st Baron Kelvin. Colour temperature is measured in Degrees Kelvin.
Compacts and DSLRs come with a selection of white balance presets, with each setting calibrated to a different lighting condition (e.g., cloudy, tungsten, daylight etc).