A camera lens is an optical device that focuses light onto a camera's sensor or film, allowing for the capture of images. Lenses come in various types, such as wide-angle, telephoto, and macro, each designed for specific photography needs. The focal length, measured in millimeters, determines how much of a scene can be captured and how close or far away subjects appear. Lenses are made up of multiple glass elements that work together to reduce distortion and improve image quality. The aperture, an adjustable opening within the lens, controls the amount of light entering the camera, affecting exposure and depth of field. Understanding these features helps photographers choose the right lens for their creative vision.