Apodizing filters from Reynard Corp. eliminate undesirable intensity variations in optical systems. Inserting a variable transmission filter at the aperture stop modifies the diffraction pattern of a lens, and the density of the filter increases radially from the outside edge toward the center. The reduced transmission at the center of the aperture improves performance at high frequencies, and reducing transmission at the edge enhances low-frequency performance. The filters are produced on a custom basis because uniformity variations are a function of the customer's optical configurations. Applications include converting a laser Gaussian distribution to a top-hat configuration by blocking certain areas and transmitting others.