Abstract: An electrostatic lens system consisting of several electrodes and a novel method of making same. The invention relates to a lithography apparatus that includes a field composable lens where at least one lens electrode has a novel structure, said structure comprising an outer support structure, an insulating intermediate part and a conductive inner part composed of a number of segment-like subelectrodes that can be individually powered, if necessary, slightly differently to produce desired individual electrostatic subfields to be superimposed to the lens field. With the field composable lens design, it has been successfully demonstrated that a number of shape and alignment errors of lens components can be corrected by supplying slightly different voltages to individual subelectrodes, thus optimizing the overall lens performance (in view of its optical properties).