Lens Test: Sigma 70–300mm f/4–5.6 DG OS AF

Lens Test: Sigma 70–300mm f/4–5.6 DG OS AF

Talk about popular: In mid-February, Sigma was offering three different versions of a 70–300mm f/4–5.6 full-frame zoom, including this new Optically Stabilized model ($400, street). It’s one of the few zooms that let Sony and Pentax shooters choose between lens-based and camerabased stabilization.

A bit heavier than the comparable Canon and Nikon stabilized 70–300mm zooms, it’s also about a half-inch shorter. The zoom and focusing rings are well proportioned, and their actions are adequately damped, but the barrel exhibits unusual zoom creep and has no lock. AF is slightly noisy and of average speed. Also, focusing is the conventional (not internal) type: The outer barrel turns during focus, and you can’t touch up focus manually in the AF mode.

We found Excellent SQF performance at 70mm and 200mm. Approaching 300mm, however, sharpness fell from Excellent through Very Good down into the Good range —not unusual in tele zooms at this price.

Better news: Our DxO Analyzer 3.2 tests of linear distortion found virtually none at 70mm and only Slight pincushioning at 200mm and 300mm. This was slightly better than the Nikon and much better than the Canon’s Visible distortion.

Light falloff was slightly better than the Nikon and far better than the Canon, which had to be stopped down to f/11 to eliminate falloff at 200mm and 300mm.

Maximum subject magnification was good (1:3.5), and in DxO blur-factor tests of the stabilization mechanism, four users averaged between 1 and 2 stops of extra handholdable sharpness— a bit below-average, and beneath Sigma’s 4-stop spec (but we rarely achieve the advantages that makers claim).

By far the least-pricey stabilized tele zoom, this lens will have a strong appeal to the budget-bound. Close-up fans will be more tempted by Sigma’s $210 70–300mm f/4–5.6 Macro zoom, with 1:2 magnification. The question is: How much are 1 or 2 extra stops of handholding worth to you?

Test Results

– Distortion: At 70mm, 0.06% (Imperceptible) pincushion; at 200mm, 0.26% (Slight) pincushion; at 300mm, 0.28% (Slight) pincushion
– Light Falloff: At 70mm, gone by f/5; at 200mm, by f/6.3; at 300mm, by f/6.3
– Close-Focusing: 58.4 inches
– Maximum Magnification Ratio: At 70mm, 1:14.94; at 200mm, 1:5.51; at 300mm, 1:3.49