Sigma 17-70mm F2.8-4 DC Macro HSM C Sony and Pentax mount lens review: Smaller, lighter and improved uniformity

Introduction Although the ‘starter’ type lenses found in camera kits are generally good-performers, Sigma’s hoping potential purchasers will either be tempted when ordering their new camera body or maybe even replace their existing 18-55mm kit lens with this faster (brighter) model.Although this recently upgraded zoom shares a similar cosmetic appearance to the firm’s Art-series this new model is the first of the new general-purpose Contemporary line. As well as a revised exterior, it features a modified optical construction consisting of 16 elements arranged in 14 groups. Like its predecessor it has has a sonic-type AF motor