Standard wide-angle to telephoto zoom lens is designed for use with full-frame Canon EF-mount DSLRs, however can also be used with APS-C models where it will provide a 38.4-168mm equivalent focal length range.. Constant f/4 maximum aperture maintains consistent illumination throughout the zoom range.. Four glass-molded aspherical elements, including one large-diameter double-sided glass-molded lens, help to minimize distortions and spherical aberrations throughout the zoom range in order to maintain edge-to-edge sharpness and illumination.. An Air Sphere Coating has been applied to individual elements to reduce backlit flaring and ghosting for greater contrast and color fidelity in strong lighting conditions.. An Optical Image Stabilizer helps to minimize the appearance of camera shake by up to four shutter speed stops to better enable working in low-light conditions and with slower shutter speeds.