A camera lens aperture is composed of four components: STOP, IRIS, ZOOM, and MACRO. STOP is a mechanism that limits the amount of light entering the lens, while IRIS is an adjustable diaphragm that controls the size of the aperture. ZOOM is a feature that allows for the adjustment of the focal length of the lens, and MACRO is a feature that allows for close-up photography. FOCUS is the process of adjusting the lens to bring the subject into sharp FOCUS.