Spanning a versatile zoom range and characterized by its bright design, the Tamron 17-70mm f/2.8 Di III-A VC RXD is a 25.5-105mm-equivalent lens for APS-C-format Sony E-mount mirrorless cameras. The w espandi...ide to short-tele range is ideal for everyday shooting and the fast f/2.8 constant maximum aperture suits working in difficult lighting conditions and offers improved control over depth of field. Complementing this design is a series of specialized optics, including aspherical and low dispersion elements, that produce well-corrected imagery with high sharpness, clarity, and color accuracy. Individual elements also feature Tamron's BBAR coating, which suppresses flare and ghosting for greater contrast when working in backlit and harsh lighting conditions.