If a camera is to be used for the special purpose of recording periodic grid-like patterns, the range of spatial frequencies which it must handle is limited, and its imaging performance for a given range can be optimized by installing a suitably slotted mask inside the lens aperture. With this modification, a standard 35 mm single lens reflex camera has been found to resolve up to 600 lines/mm in both vertical and horizontal directions across the full format. The tuned response of this camera makes it well adapted for measuring lateral displacements of large incoherently lit structures by the moire grid technique. Some preliminary results are described, and the technique is compared to laser speckle photography.