Individual elements also feature Tamron's BBAR coating, which suppresses flare and ghosting for greater contrast when working in backlit and harsh lighting conditions The 17-28mm f/2.8 Di III RXD from Tamron is a versatile zoom for full-frame Sony E-mount mirrorless cameras Covering ultra-wide to wide focal lengths, this lens is particularly suitable for landscape, astrophotography, and architectural shooting Its bright f/2.8 constant maximum aperture complements this range and affords increased control over depth of field along with enhanced low-light performance The optical design incorporates a both XLD and LD elements The Tamron 17-28mm f/2.8 Di III RXD Lens Model A046 achieves an astonishingly small diameter for a high-speed ultra-wide-angle zoom lens, as witnessed by its modest 67mm filter size. Its unprecedented light weight and compact size provide excellent balance when used with a full-frame mirrorless camera, making it easy to carry, and enabling it to cater to a wide range of scenes and shooting conditions. The Model A046 offers a fast F/2.8 aperture throughout the entire zoom range and delivers high-resolution and contrast edge to edge. The combination of ultra-wide-angle focal length, fast constant F/2.8 aperture and Minimum Object Distance of 7.5 in at the wide-angle end encourages richly expressive and creative photography in a multitude of scenarios. The Model A046's AF drive system is powered by the RXD (Rapid eXtra-silent stepping Drive) stepping motor unit, enabling it to deliver high-speed, high-precision and superbly quiet operation suitable for shooting video as well as still photographs.