SLR owners looking to upgrade lenses often must choose between their camera maker's lenses and less expensive third-party models that often aren't as good. But the solid competence of Sigma's $1,250 APO 70-200mm F2.8 EX DG OS HSM makes this lens a great compromise of high quality and good value.
Sigma's fast telephoto zoom is image-stabilized, optically strong, and sturdily built. I tried the Canon version on a full-frame EOS 5D Mark III, where the zoom range is versatile enough to handle indoor portraiture, outdoor architecture, and plenty more.
There's strong competition here from the big boys in the SLR market. From Nikon, there's the $2,400 Nikkor 70-200mm f/2.8G ED VR II and the new $1,400 AF-S Nikkor 70-200mm f/4G ED VR. From Canon, there's the $1,100 EF 70-200mm f/4L IS and $2,500 EF 70-200mm f/2.8L IS II, both built like tanks and optically superb.
The Sigma 70-200mm is best of both worlds: the wide aperture of the higher-end f2.8 models at the price of the lower-end f4 models. The sharpness isn't quite up to the standard of the in-house telephoto zooms, and you won't get things like in-camera correction of vignetting and chromatic aberration that only work with first-party lenses. But the lens is quite competitive for its price.
I shot everything from dinner parties and speeches, where I appreciated the wide aperture's usefulness in dim light, to nature and architecture scenes, where the lens' sharpness across the whole frame when stopped down came into its own.
Optics are good, with reasonable center-frame sharpness at f2.8 and terrific performance at f8. Vignetting at f2.8 is definitely noticeable, but as with sharpness, it's often mostly a nonissue: you're often shooting wide open to deliberately blur out the background. Distortion is manageable, and chromatic aberration is pleasantly low.
Shooting portraits at f2.8 is a pleasure, with nice bokeh -- the smooth blurring of out-of-focus backgrounds to keep them from being distracting.
The autofocus is reasonable, though louder and not as fast as on rival Canon telephotos I've used in this zoom range. On a few rare occasions, the lens autofocus objected with a bit of vibration when having trouble locking onto the subject. The lens makes no pretense at being a macro, with a close-focus distance of 1.4 meters; the Canon competitors' close-focus distance of 1.2 meters a significant improvement.
The included petal-shaped lens hood keeps lens flare under control most of the time. The lens also comes with a tripod mount.
The lens is heavyish but par for the course given the full-frame support, durability, and wide aperture. It weighs 3.15 pounds (1.43 kg) and is 3.4 inches in diameter by 7.8 inches long (8.6x19.8cm) without the lens hood attached. It's easy to shoot with it handheld, though not nearly as easy as with the smaller, lighter Canon EF 70-200mm f4L IS, especially after a full day carrying it around.
Sigma has been bringing anti-shake technology to its lenses, designated by OS (optical stabilization) in the name, and I found it very useful on the 70-200mm lens. A side-mounted switch can disable OS, configure it for ordinary use, or set it for horizontal panning situations like trying to photograph a moving racecar. I could capture shots with exposure times as long as 1/10 sec. when zoomed all the way to 200mm -- though certainly not every shot. The OS is quieter than on many Canon lenses, too, which is welcome when shooting video.
The lens is available with Canon, Nikon, Pentax, Sony, and Sigma mounts.
This Sigma 70-200mm doesn't match Canon's telephoto zooms for top-shelf sharpness, but it's a very good lens.