Lenses or Camera Lens is basically a type of optical lens that is used together with the Camera to enhance the quality of images or video in terms of improving focus or zooming the far away objects. Today, many camera models come along with a lens which may be fixed permanently or interchangeable.The basic operation of the lens involves focusing, which is done by changing the distance between the lens assembly and the image plane, or by changing the elements of the lens assembly. Many lenses today come with a Cam system feature wherein the distance between the groups is adjusted while the lens is focused.
Optical Lenses work on two parameters, Focal Length and Maximum Aperture. Focal length helps in finding out the image magnification that is projected on the image plane by determining that angle of view.The Aperture determines the intensity of the light of the image. Focal Lengths are specified in mm (millimeter) and on the basis of their size, they are called as Normal, Wide-Angle and Long-Focus Lens. Two types of Common Lenses are: Zoom Lens wherein the focal length depends on the movement of the internal elements.The second type is called the Macro or "Close-up" Lens. Some of the famous companies that manufacture lens are: Tamron, Canon, Sony, Olympus, Nikon etc.