Lenses and accessories
A camera lens (also known as photographic lens or photographic objective) is an opticallens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.
The lens of the camera is the main part of the camera and is collecting the rays of an optical system designed to produce a real image optical objects of the world.
The creative use of the lens gives photography its expressive qualities - they shape the way you “see” the world through the viewfinder. From the properties of the lens depends on the quality of the resulting image.
A primary characteristic of a lens is the focal length. A lens’ focal length is defined as the distance between the lens’ optical center and the camera’s image sensor (or film plane) when focused at infinity. A camera lens may be made from a number of elements: from one to over 20 in the more complex zooms. These elements may themselves comprise a group of lenses cemented together. The lens mount design is an important issue for compatibility between cameras and lenses. So a photographer shouldn't forget about the adapter to set the lens on the camera.