Whether you’re a hobbyist looking to upgrade from that cheap kit lens or an aspiring photojournalist seeking a versatile lens within a tight budget, the Sigma 17-70 is worth your attention.
After a while, that 18-55mm kit lens that came with your camera may start to feel limiting, and you may come to realize that many of the images are a little on the soft side. That’s when lenses like the Sigma 17-70mm f/2.8-4 DC Macro OS HSM zoom come in. The 17-70 has been a popular Sigma staple for years, but it was missing one thing: Optical Stabilization (OS). The new version has it—as well as macro focusing down to 8.7 inches and magnification ratio of 1:2.7.
While a lens of this kind of design is primarily intended for prosumers and serious hobbyists, it may also be worth considering by photojournalists who are just starting out and have limited budgets.
The lens is designed for cameras with APS-sized sensors, and is not recommended for use with 35mm film or full-frame sensor cameras. Available in Nikon (including cameras that don’t have built-in focus motors, like the D5000), Canon, Sigma, Sony and Pentax mounts, it lists for $680 but expect to pay about $450 for it at Adorama.
I put a sample lens through its paces, mounted on a Canon EOS 40D, to find out.
Look and Feel
The matte black lens barrel has clear, legible white letters indicating focus, focal length and magnification, plus a wide, ribbed rubber zoom ring and a thinner focus ring. Both offer enough size and grip for easy operation. I found the zoom ring to offer a fair amount of resistance—I felt it needed a bit more effort than typical to zoom in or out. However, I also found that there was absolutely no zoom creep.
A Zoom lock on the side of the lens barrel locks the zoom in at 17mm. It would be better if one could lock in any chosen focal length. An AF/MF (autofocus/manual focus) switch lets you choose to take control of focus. If you are in AF mode, you’ll know immediately, as the focus ring will put up considerable resistance if you try to rotate it. It is nice and smooth in manual focus mode.
Then there’s the lens’s newest feature, the OS on/off switch. I recommend keeping it turned on at all times when shooting hand-held. I found it gained me two stops of exposure in field tests.
Finally, the mount. Unlike the plastic mounts you are likely going to find on the typical kit lens these days, the Sigma’s mount is solid metal, indicating the lens’s solid build and feel.
In use, I found focus to be fast and fairly quiet in most cases, although the lens was spooked by some low-contrast subjects and would search focus for several seconds.
At the full wide-angle setting, images were amazingly sharp, and that sharpness was maintained until about 35-50mm. At the longer end of the zoom range, images were still pretty sharp in the center but showed some blur at the corners when shooting at the widest aperture. Sharpness improved when I shot at a middle aperture like f/8.
Storm damage: Huge downed tree in front of older Highland Park, NJ house, shot two days after a major storm blew through the area; under optimal shooting at wide angle, images were tack-sharp.
Same tree heavily damaged a car sitting in the driveway of the house next door. Shot at 70mm, sharpness continues to be excellent.
The camera’s two Aspherical and single SLD glass element work together to deliver outstanding contrast and sharpness, and the result is quite good. Flare is well controlled throughout the focal range. Moderate pillow distortion at 17mm disappears by around 50mm but ever-so-slight pincussion distortion appears at around 70mm.
Park closed! Donaldson Park in Highland Park, NJ was closed due to flooding caused by the Raritan River overflowing its banks and preventing me from shooting test shots in my usual spot. Shooting towards the sun at 24mm, flare is well controlled.
Flood reflections: The sun is reflected off water gathered on what should be a little league baseball diamond. This shots demonstrates that even at the telephoto setting, while there is a little flare, it is quite well controlled.
At 17mm, purple/yellow fringing was apparent, although this virtually disappears by 50mm. There is some vignetting at the widest angle which modify as you zoom in. Bokeh is standard; the seven hard edges of the aperture leaves are visible in specular highlights. There is slight double-image blur of thin out-of-focus objects.
The first flowers of spring! I found macro focus to be quite sharp with excellent contrast at all focal lengths. This was shot at approximately 9 inches at the 70mm. Notice the double-image bokeh blur of the blade of grass towards the upper right.
Sigma was wise to add Optical Stabilization to its already-popular 17-70mm f/2.8-4 lens because it increases its usefulness. The lens is solidly built, performed admirably, and delivered nice, sharp pictures. If you’re a photojournalist, this lens may be a good starter optic, although I have a feeling you would soon hanker for a fixed f/2.8 maximum aperture model. But if you’re a serious photo hobbyist who has outgrown your kit lens, this one is an excellent way to step up.