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Sigma 17-50mm F2.8 EX DC OS HSM Review
The Sigma 17-50mm F2.8 EX DC OS HSM Lens is a standard zoom for APS-C digital cameras. The lens has a fast f/2.8 aperture through its zoom range, but isn’t that sharp when shot wide open.
(3.5 out of 5)
- Fixed f/2.8 aperture
- Useful zoom range
- Includes hood
- Optical image stabilization.
- Soft wide open.
The Sigma 17-50mm F2.8 EX DC OS HSM ($980 list) is a standard zoom lens for APS-C cameras. Like most Sigma lenses, it’s available in a variety of lens mounts—Canon, Nikon, Sony/Minolta, Pentax, and Sigma in this case. It covers about a 25-75mm field of view in classic 35mm photography, a focal range that can handle everything from wide landscapes to snapshots to portraits. The maximum f/2.8 aperture makes it possible to shoot in a variety of lighting conditions, and to blur the background behind your subject.
The lens itself is fairly squat, measuring 3.6 by 3.3 inches (HD), and somewhat heavy at 1.24 pounds. It does extend while zooming, but the front element doesn’t rotate, so using a polarizer filter is a possible—the thread size is 77mm. There’s a physical lock to keep the lens retracted when it’s in your bag, and a switch to toggle between autofocus and manual focus operation. There are also switches to toggle between manual and autofocus operation, and to enable or disable the optical stabilization system that is built into the lens. A hood is included, which adds some size to the lens when in use, but will help increase contrast and reduce the occurrence of lens flares.
I used Imatest to measure the sharpness and distortion of the lens, paired with the Sigma SD1 Merrill ($2,299, 2.5 stars). At its widest aperture, the lens fell a bit short of the 1,800 lines per picture height required for a sharp photo. At 17mm it managed about 1,628 lines at f/2.8, which increased to a much more impressive 2,240 lines at f/4. There’s also a quite noticeable 2.7 percent of barrel distortion at this focal length, which will rear its head when shooting scenes with straight lines—they’ll appear as curved as the metal rims of a wooden barrel.
The lens’s performance drops a bit at the midpoint of its zoom range. At 35mm it scores about 1,658 lines at f/2.8, which increases to a sharp 1,968 lines at f/4, and 2,105 at f/5.6—all with negligible distortion. At 50mm the lens records 1,790 lines at f/2.8, increases to 1,970 lines at f/4, and tops out at 2,038 lines at f/5.6. Distortion is aminor issue at this focal length—the lens displays 1 percent of pincushion distortion here. In terms of sharpness, the lens is disappointing compared with a comparable lens that we’ve tested—the Sony 16-50mm f/2.8 Standard Zoom ($699.99) managed better than 2,100 lines at its widest, 1,800 lines at 35mm, and 1,900 lines at 50mm—all at its widest f/2.8 aperture. The Sony lens does show a bit more distortion at 16mm—3.6 percent.
If you’re looking to upgrade the 18-55mm kit lens that was likely bundled with your D-SLR, the Sigma 17-50mm F2.8 EX DC OS HSM is an appealing option. It’s got a fast aperture, a very useful zoom range, and it’s priced less than the similar Canon EF-S 17-55mm f/2.8 IS USM ($1,179), Nikon AF-S DX Zoom-Nikkor 17-55mm f/2.8G IF-ED ($1,539.95), and Pentax DA* 16-50mm F2.8 ED/AL (IF) ($1,499.95) lenses. If you’re an owner of one of those systems, you’ll have to decide if the somewhat soft images produced by the Sigma 17-50mm at f/2.8 are worth the savings. If you’re a Sony shooter, the choice is obvious—the Sony 16-50mm f/2.8 Standard Zoom is a better lens, and it’s less expensive.
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By Jim Fisher, PCMag