Apple's latest patent application details a new camera flash system that would optimize the flash based on the photo's subject. It combines a flash redirector, imaging sensors that concentrate on scene conditions, and a touch screen.
This combination of these elements could be used to provide the equivalent of a touch-to-focus for light for dark areas of a soon-to-be photograph: a touch-to-illuminate feature. The system could be incorporated into iOS devices, the iMac, MacBooks, and even a dedicated video camera. [Patently Apple]