A concave lens is the type of lens that is thinner from the center but has thicker edges. This lens has the ability to spread the light rays, also known as a diverging lens. The image formed by the concave lens is always smaller than the object. The image is also virtual and upright. The size of the image also depends upon the distance of the object from the lens. Concave lenses are used in telescopes, side mirrors, movie projectors, etc.