Sigma 17-70mm f/2.8-4 DC Macro OS HS M | C £350/$500
Newer and smaller, but with a bigger zoom range
The newer of Sigma’s DX-format lenses on test, this one is a ‘Contemporary’ class model from Sigma’s ‘Global Vision’ line-up. As such, it’s designed to be compact, lightweight and stylish. It lacks the older Sigma lens’s constant-aperture rating, but matches its f/2.8 rating at the short end of the zoom range, while only shrinking to f/4 at the long end. That’s still an f/stop faster than most kit lenses.
As with the Sigma 17-50mm lens, autofocus is based on an ultrasonic motor, and the focus ring rotates during autofocus, so you have to be careful to keep your fingers clear. Other similarities are the inclusion of two FLD elements and a four-stop optical stabilizer.
Lab test results for centresharpness aren’t quite as good as from the Sigma 17-50mm, but levels of sharpness are much more consistent across the whole image frame. There’s less colour fringing at mid to long zoom settings, and pincushion distortion at the long end is barely any worse, despite the extra telephoto reach.