Lens
An optical device that focuses light rays. In cameras, the lens is the device on the front face (or in a tube extending from the front face) that gathers the incoming light and concentrates it so that it can be directed toward the film (in an optical camera) or the imaging device (in a digital camera).
Wide angle lens - A lens that has an angle of view greater than that of a standard lens and that is considered of short focal length. This kind of lens is usually employed to include more of a subject within the confines of the image frame.
Zoom lens - Lens with variable focal length within a certain range.Fixed focal lens - A lens in which the focus is preset and is not adjustable.
Fish Eye Lens - This is an extremely wide-angle lens. A fish-eye lens magnifies the parts of the image near the center of the image and reduces the parts that are far away from the center.Macro Lens - Lens that allows close photography; also called a close up lens.