Lens

Anatomy of a Lens

Elements

An element is an individual glass structure in a lens that is not permanantly, directly fixed to any other element. In older lenses an element was an individual piece of glass but more modern lenses make use of some composite elements which are two or more pieces of glass cemented together.

Barrel

The barrel is the tube-shaped outer shell that contains the lens elements.

Aperture

An aperture is an opening in a lens that limits the amount of light passing through it to the camera body. The term aperture is also often used to describe the diameter of that opening. It is usually adjustable, most often by turning an "aperture ring" on the outside of the lens body.

Mount

A lens mount is the part of an interchangeable system lens that connects to the camera body.