Manufacturer of spherical lens —— Spherical lens has constant curvature from the center to the edge of the lens, while aspheric lens has continuous curvature change from the center to the edge. In the photographic lens, in order to ensure the optical performance, many "aberrations" must be corrected. If only spherical lens is used for correction, many lens combinations are needed for the technical requirements of the corresponding lens. For the special advanced lens, only using spherical lens sometimes can not make the aberration correction to the user's satisfaction.
