1. A vision system comprising: a controllable lighting system; an imaging system; and a light intensity control system, wherein: the light intensity control system is operable to determine a prescribed illumination setting usable to achieve a desired image characteristic in a region of interest to be imaged by the vision system, the prescribed illumination setting determined based on a plurality of actual images corresponding to actual illumination settings; and the prescribed illumination setting is typically different from any of the actual illumination settings.