a lens that is convex on one side and concave on the other.
Lens used to shorten the focal length of a doublet.
A lens that has one convex surface and a concave surface.
Lens with one surface convex and the other concave.
A lens with one side convex and the other side concave.
Simple lens consisting of a single piece off glass, thicker at the center than at the edges. It has one concave and one convex face.