Described is a telecentric illuminator that can be used, for example, in a mask aligner system for semiconductor wafer processing or as part of a solar simulator system for characterization of solar cells. The telecentric illuminator includes a tapered optic, a lens group having a plurality of lenses and an aperture stop, and a hybrid Fresnel lens. The Fresnel lens is disposed at a position along the optical axis of the telecentric illuminator to generate a telecentric image of the aperture stop at an illumination plane. The Fresnel lens may have a curved central portion and the aperture stop may be apodized to achieve desired illumination characteristics and improve the resolution of a mask aligner system.