The 17-28mm f/2.8 Di III RXD from Tamron is a versatile zoom for full-frame Sony E-mount mirrorless cameras. The optical design incorporates both XLD and LD elements, which produce a highly corrected image with reduced chromatic aberrations and color fringing for improved clarity and color accuracy.  Additionally, adding to the versatility, an RXD stepping motor enables quick, near-silent autofocus performance to suit stills and video, along with a full-time manual focus override and a minimum focusing distance of 7.5". Versatile wide-angle zoom is designed for full-frame Sony E-mount mirrorless cameras, however, can also be used with APS-C models where it will provide a 25.5-42mm equivalent focal length range. A moisture-resistant construction benefits this lens' use in inclement conditions and a fluorine coating has also been applied to the front lens element to protect against dust, dirt, and smearing.