The disclosed bar code reader includes an auto-focusing component for rapidly producing in focus images. An imaging system makes use of an aiming pattern that impinges upon the coded indicia of a target. The imaging system includes a light monitoring pixel array and a focusing lens that is fixed with respect to the pixel array for transmitting an image of the target object onto the pixel array. The bar code reader also includes an illumination system comprising one or more light emitting diodes for illuminating a the target within a field of view defined by the optical system. A drive circuit coupled to the light emitting diodes of the illumination system including at least one energy storage capacitor for providing an electrical pulse that illuminates the target. A controller selectively energizes the light emitting diodes by discharging the at least one capacitor of the drive circuit.