Sigma 70-300mm f/4-5.6 DG OS £399
20th Nov 2011 | 17:45
Completely redesigned, this zoom lens isn't just an old dog with new tricks
At a glance, it's easy to think that this is a newer version of Sigma's 70-300mm f/4-5.6 APO DG Macro lens, but with an optical stabiliser fitted (OS). Sure enough, the Sigma 70-300mm f/4-5.6 DG OS is still a 'DG' lens designed for full-frame DSLRs and equally compatible with APS-C bodies that have smaller image sensors, but it's a completely different lens.
Available in various mount options for Canon, Nikon, Pentax, Sigma and Sony bodies, the effective zoom range is 112-480mm on Canon APS-C cameras and 105-450mm in all other fitments.
On current Pentax and Sony bodies, you get the choice of whether to use the Sigma's optical stabiliser or sensor-shift stabilisation featured in the camera. Using both stabilisers simultaneously can lead to problems and, in our tests, we've found the in-lens optical stabilisation works rather better, especially at long telephoto zoom settings.
There's no HyperSonic Motor (HSM) autofocus actuator, the lens relying instead on a standard electric motor. By contrast, the OS is relatively high-tech and delivers a 4-stop advantage in beating camera-shake.
Unlike the cheaper Sigma 70-300mm APO, the Sigma 70-300mm f/4-5.6 DG OS lens features just one Special Low Dispersion (SLD) element rather than three.
Overall, there are 16 elements built into 11 groups and a 9-blade diaphragm which enables an aperture range of f/4-5.6 to f/22-32. Another crucial difference is that this lens lacks the APO version's macro facility, the maximum magnification factor being 0.25x instead of 0.5x.
Build quality, handling and performance
Build quality and handling
A little heavier than Sigma's 70-300mm APO lens, the Sigma 70-300mm f/4-5.6 DG OS weighs 610g and is 4mm longer, at 77 x 117mm. Focusing isn't internal so the front element rotates and extends, the maximum length being 235mm at the longest zoom setting and closest focus distance, measured with the hood fitted.
Like Sigma's other 50-200mm OS and 70-300mm APO telephoto zooms, build quality is of a high standard and construction feels sturdy. There's no zoom creep but the zoom ring and manual focus ring operate smoothly and effectively.
The latter is fitted at the front of the lens barrel and, given the length of the lens, it's quite easy to avoid fouling its action in autofocus mode while it's rotating. The downside is that the front element also rotates during focusing, which can be a problem when using rotation-critical filters such as a circular polariser.
In our tests, the stabiliser in the Sigma 70-300mm f/4-5.6 DG OS lens lived up to its 4-stop claims and performed more consistently than the one in Sigma's smaller 50-200mm OS, which is designed only for APS-C cameras rather than also being full-frame compatible.
The lens is a worthy update to Sigma's older 70-300mm APO Macro model.
Despite lacking the earlier lens's Apochromatic (APO) badge, chromatic aberrations were actually slightly less noticeable in our tests, while sharpness was rather better when shooting at the longest telephoto setting of 300mm and the largest available aperture of f/5.6.
Taken at 300mm, f/5.6
Optical quality is good and the 4-stop optical stabiliser performs well, but it's a shame that Sigma didn't fit an HyperSonic Motor (HSM) autofocus system to the Sigma 70-300mm f/4-5.6 DG OS. As it is, the basic electric motor is quite noisy, but at least it's not too sluggish in operation.
The 4-stop optical stabiliser makes for consistently sharp handheld shots, and the build quality feels robust.
It lacks HSM autofocus and the front element rotates and extends during focusing.
Overall, the Sigma 70-300mm f/4-5.6 DG OS is a good buy at the price, but it's still outclassed by the more expensive Nikon 70-300mm VR and Tamron 70-300mm VC USD lenses.