The 17-70mm F2.8 maintains its large F2.8 maximum aperture throughout the entire zoom range (unlike variable aperture lenses that darken as you zoom). Thanks to F2.8 and high optical performance, 17-70mm F2.8 allows you to capture your subjects with clear details from wide angle to telephoto. The three main advantages of a large F2.8 aperture are: A) ability to shoot successfully in lower light levels, B) beautiful and dreamy bokeh, and C) better control of depth-of-field which is particularly useful when intentionally limiting depth-of-field to improve portraits by blurring the area behind the main subject. Structurally, the optical formula includes 16 elements in 12 groups.

This lens was created through the uncompromising pursuit of portability optimized for use with APS-C Sony E-mount cameras. Even with the inclusion of high-performance VC, the 17-70mm F2.8 is extremely light weight and compact, with an overall length of just 119.3mm (4.7 in), maximum diameter of 74.6mm, and weight of 525g (18.5 oz). It is a very versatile lens for travel, where small bags are preferred, and is a great portable lens for daily use. The AF drive on the 17-70mm F2.8 includes an RXD motor unit to help you stay focused on the action. RXD uses an actuator to precisely control the rotational angle of the motor, allowing it to directly drive the focusing lens without passing through a reduction gear.

This versatile zoom lens lets you enjoy shooting in a multitude of genres, from wide-angle scenes to telephoto moments. With a focal length range of 17mm to 70mm (a full-frame equivalent of 25.5-105mm), this is the world's first large aperture F2.8 standard zoom lens for APS-C mirrorless cameras to achieve a 4.1x zoom ratio. It’s ideal for a variety of scenarios, from portraits and street snapshots, to landscapes and even close-ups. The 17-70mm F2.8 utilizes Tamron's highly regarded, proprietary VC image stabilization system to maximize the inherent optical performance of the lens. It reduces the degradation of picture quality caused by minute camera shake that is likely to occur during handheld shooting at slow shutter speeds under low-light conditions indoors or at dusk.

This advanced lens focuses extremely close for a standard zoom lens for APS-C mirrorless cameras. The MOD (Minimum Object Distance) is just 0.19m (7.5 in) at the wide-angle end and 0.39m (15.4 in) at the telephoto end. When shooting very close to the subject, the lens enables expressive imagery with highly blurred backgrounds, a feature unique to large-aperture lenses. This allows you to create one-of-a-kind photo of a variety of subjects, from snapshots to portraits, landscapes and even architectural photography. Close-up shots of scenery taken at the 17mm end maximize the unique perspective only true wide-angle lenses can deliver.