Spherical singlets are a better choice for many applications where aberrations are not critical because they are the simplest and cheapest lens types. For simple applications, standard plano-convex, plano-concave, lenticular, and biconcave lenses are sufficient. For better performance, the optimal profile lens is optimized to maintain a spherical surface while reducing aberrations. Using multiple lens elements within a composite optical system can achieve more performance improvements. Lens lenses are usually used in these multi-element optical systems, although they are rarely used individually. For demanding applications, spherical single lenses will not perform as well as achromatic lenses (for both broadband and monochromatic light sources) or aspheric lenses (for monochromatic light sources). For more details on other types of lenses see achromat and aspheric lens sensor lenses
