Abstract: A system and method use a pattern generator to pattern illumination that is projected using an adjustable projection system to form one or more devices on a substrate. The adjustable projection system includes at least one active mirror, which is adjusted to compensate for errors found on a surface of the pattern generator, the substrate, and or an optical element in the lithography system. In one example, the adjustable projection system includes two concave and one convex mirrors, while in another system the adjustable projection system also includes one or two fold mirrors. At least one of the mirrors in these two examples is an active mirror, which is used for the compensating. In this arrangement, local focus and/or magnification errors can be substantially reduced or eliminated.