The Types of Lenses

Lenses and Refraction Light

A lens is a transparent object  that forms an image by refracting , or bending, light. Shape classifies lenses. There are two types of lenses, convex and concave lenses. Like mirrors, lenses have a focal point and an optical axis.

Convex Lenses

A lens that is thicker in the middle than at the edges is a convex lens. Convex lenses form different kinds of images. Two kinds of images that can be formed is a virtual image and real image.
These types of lenses can form a real image that is larger than the object if the object is between 1 and 2 focal lengths away from the lens.
A Virtual image is formed when an object is less than 1 focal length away from a convex lens. This image would be larger than the object itself.
A real image is formed when an object is more than 2 focal lengths away from the lens. The image is smaller than the object.



Concave Lenses

A concave lens is a lens that is thinner in the middle than at the edges. When light rays enter a concave lens parallel to the optical axis, it always bends away from each other and appear to come from a focal point in front of the lens. The rays never meet. These types of reasons do not form real images due to this. Instead they form virtual images.
These types of lenses are sometimes combined with other lenses in telescopes. The combination of these lenses produce clear images of distant objects.