Blending a sleek form-factor with a versatile working range, the 28-75mm f/2.8 Di III RXDfrom Tamron is a full-frame-compatible lens for Sony E-mount mirrorless cameras. Spanning wide-angle to portrait-length, a constant f/2.8 maximum aperture complements this range and affords increased control over depth of field along with enhanced low-light performance. The optical design incorporates a series of low dispersion and aspherical elements, which produce a highly corrected image with reduced spherical and chromatic aberrations for improved sharpness and clarity. Elements also feature Tamron's BBAR coating, which suppresses flare and ghosting for greater contrast and color fidelity when working in backlit and harsh lighting conditions. Benefitting the optical design is an RXD stepping motor, which enables quick, near-silent autofocus performance to suit stills and video, along with full-time manual focus override and a minimum focusing distance of 7.5". Suiting this lens's use in harsh climates, it also sports a moisture-resistant construction along with a fluorine-coated front element to protect against fingerprints and smudging.