An imaging reader includes an illuminating light assembly, an illuminating control operative to control either the intensity or the duration of the illumination light projected by the illuminating light assembly, and a solid-state imager. The solid-state imager includes a matrix of optical-sensors and a signal processing circuit coupled to the matrix of optical-sensors. The controller is operative to determine the optimized exposure level of the illuminating control and the optimized gain of the signal processing circuit based on a measured voltage of a voltage power source for the solid-state imager.