The new Sigma 28-45mm f/1.8 DG DN | Art is claimed to be the first full-frame zoom lens with a constant maximum aperture of f/1.8. Sigma says that this fast zoom delivers sharpness and clarity comparable to that of a prime lens throughout the range. Sigma has already pioneered fast zooms with the 18-35mm f/1.8 DC HSM | Art and the 25-35 f/2 DG HSM and the DN (digital native) 28-45mm f/1.8 adds to this impressive line up to join the latest lenses designed expressly for mirrorless cameras.