Review by Klaus Schroiff, published October 2018

Introduction

One of those lenses is the Sigma 24-70mm f/2.8 HSM DG OS ART. While the optical specs don't offer anything unusual, it has at least one additional feature compared to its Canon counterpart - an image stabilizer - and that alone broadens the appeal quite a bit. That being said, it is not unique in this respect - a few days ago we reviewed the Tamron SP 24-70mm f/2.8 Di VC USD G2 which features Tamron's variant of an image stabilizer and a good one apparently. So let's see how the Sigma performs especially compared to this lens. The typical market price for the 24-70mm f/2.8 HSM DG OS ART is around the 1300USD/1200EUR mark - or about 100USD/EUR more than the Tamron lens albeit it's still way more affordable than the Canon L (~1700USD/1600EUR).

The 24-70mm f/2.8 follows the design philosophy of all Sigma Art lenses thus the lens tube consists of a mixture of metal and TSC (Thermally Stable Composite) elements, giving an impression of very high if not great quality. Sigma classifies this lens as dust and splash-proof - which is standard in this lens and price class, of course. On the downside, the lens extends when zooming out but the inner lens tube doesn't wobble even when fully extended. Both the broad zoom ring as well as the smaller focus ring operate smoothly. A petal-shaped lens hood is supplied.

The lens features HSM, which is Sigma's version of an ultrasonic AF drive. The AF is virtually silent and quite fast. The AF accuracy of the tested sample was relatively good albeit not perfect. The image stabilizer (OS = optical stabilizer) is rated with an efficiency of up to 4 f-stops but we'd rather say it is about half of that in real life. The Tamron SP is certainly superior in this respect.

The Sigma 24-70mm f/2.8 HSM DG OS ART is compatible with Sigma USB dock, so you can fine-tune the AF calibration if you see the need and are willing to invest a little in the extra accessory.