Positive Meniscus Lenses

A meniscus lens is a lens with a concave surface on one side and a convex surface on the other. A positive meniscus lens has a positive focal length with its convex surface having a smaller radius of curvature than the concave surface, thus possessing a positive focal length and being usable as a magnifier. Meniscus lenses can correct aberrations and are commonly used as corrective lenses; they can also serve as condensers in illumination systems, and can achieve the effect of chromatic aberration elimination when an appropriate thickness is selected.