A spherical lens, with surfaces formed from the surfaces of two spheres, is a common lens type including double convex, plano-convex, double concave, and plano-concave lenses. They have a focal point and length, with convex lenses focusing light and concave lenses diverging light. These lenses can suffer from spherical aberration, a distortion that can be corrected or minimized. Convex lenses form real images while concave lenses form virtual ones. The lens material, which can range from glass to plastic, significantly impacts its properties. Spherical lenses are used widely, from magnifying glasses to scientific instruments, and are generally more cost-effective than aspheric lenses.
