The repeatability of strobe illumination for image exposure is improved over a wide dynamic range in a machine vision system wherein a relationship between a camera integration period and a pulse duration of a strobe light generator control the effective exposure of a camera image during a timing overlap between a beginning of the camera integration period and an end of the pulse duration. To avoid noise in the illumination, the illumination pulse duration may start, the camera integration period may begin after a delay relative to that start and not later than the end of the pulse duration, the pulse duration may end, and the camera integration period may end not earlier than the end of the pulse duration. The timing overlap may also be synchronized with a periodic ripple component in the strobe illumination, to provide improved repeatability.