Sigma 14-24mm F2.8 DG DN ArtAn Art series zoom, this lens is also distinguished by its fast f 2. 8 constant maximum aperture to suit working in available lighting conditions. Featuring a sophisticated optical design, a series of low dispersion and aspherical elements is used to minimize both chromatic and spherical aberrations throughout the zoom range in order to achieve high sharpness, clarity, and color accuracy. A Super Multi Layer Coating combined with a Nano Porous Coating