The standard wide-angle to telephoto zoom lens is made to work with full-frame Canon EF-mount DSLRs, but it can also be used with APS-C models, which have a focal length range of 38.4 to 168 mm. Throughout the zoom range, constant illumination is maintained by a constant f/4 maximum aperture. In order to preserve edge-to-edge sharpness and illumination, four glass-molded aspherical components—including one large-diameter double-sided glass-molded lens—help to reduce distortions and spherical aberrations across the zoom range. To improve contrast and color fidelity under harsh lighting conditions, an Air Sphere Coating has been applied to individual elements to lessen backlit flaring and ghosting. By reducing the appearance of camera shake by up to four shutter speed stops, an optical image stabilizer makes it easier to work in low light.