SIGMA’s aspherical lens technology contributes to outstanding optical performance and compact dimensions. These aspherical lens elements com pensate for the spherical aberration and distortion which cannot be completely eliminated using con ventional spherical lens elements alone. They are also key to reducing the size and weight of high-pow er zooms and other large lenses while improving im age quality. SIGMA has two kinds of aspherical lens technologies. Hybrid aspherical lens elements are made by forming a polymer in an aspherical shape on a glass lens surface. Precision-molded glass aspherical lens elements are made by direct forming.