A system that comprises a receiver port to receive lens system design specifications; and a processor to: select a lens system type that includes one or more preliminary lenses, the selecting based, at least in part, on the lens system design specifications; from a lens database, select one or more catalog lenses to add to or replace the one or more preliminary lenses of the lens system type to construct a lens system; vary distances between or among the one or more catalog lenses and/or the one or more preliminary lenses of the lens system; and as the distances vary, determine optical behavior of the lens system.