I've now owned Nikon's elaborately named "AF-S DX NIKKOR 16-85mm f/3.5-5.6G ED VR" lens for well over two years, and I'm incredibly happy with it. The excellent focal range makes it a superb walk-around lens. The 16mm wide-end is really something special on a "normal" range DX zoom, since most only go as wide as 18mm. Its superb sharpness when combined with those extra 2mm make for a very capable landscape lens. The brilliant optical stabilization system (Nikon's VR) makes getting hand-held low-light shots a breeze.
All of these characteristics make it an absolutely oustanding lens, especially for casual travelers. Photographing the interior of a dimly-lit cathedral? No problem: the 16mm wide end and VR stabilization make it a breeze. Want to capture the some of the exterior architectural details? Again, no big deal: the 85mm long end and superb sharpness can make it happen.
These features all add up to mean that it has been my primary travel and walk-around lens ever since I purchased it back in 2009. Many of the most viewed images in my portfolio have been taken with it:
So, what is there to complain about? Not much, but I've always wanted something that's a bit faster. Constant fast-aperture "normal" zoom lenses are great for subject isolation at events like weddings, and their focal length coverage means that they're also handy all sorts of other things (including landscapes). They can also make for excellent travel lenses. One can easily go from shooting serene landscapes (stopped-down a bit at the wide-end), to beautiful portraits (wide-open at the long end) without having to swap lenses.
Nikon makes a well-reviewed 17-55mm f/2.8 zoom, but it lacks VR stabilization and is quite expensive (around $1500 at the time of this article's publication). Fortuantely, Sigma has recently released the stabilized "17-50mm f/2.8 EX DC OS HSM". At $670, it's comparatively priced to Nikon's 16-85 VR which sells for $650. The Sigma gives up 1mm on the wide end and 35mm on the long end, but makes up for it with an f/2.8 constant fast aperture. It's also worth noting that the Sigma has a more common 77mm filter thread, while the Nikon 16-85 uses 67mm filters.
Photozone.de has excellent technical reviews of both of these lenses. You can compare the resolution, distortion, abberations, bokeh, and other factors at the links below:
On paper the 16-85 VR is a bit sharper than the 17-50 OS when stopped down to their sharpest settings (f/8.0 and f/5.6, respectively). The 17-50 is actually quite sharp in the center when wide-open, which is great news for the casual portrait photographer. But the real question is, how do they stack up against each other, image-for-image? Let's find out.
Field of View
Below are some GIF images which compare the lenses at their different settings.
As you can see, the 16-85 VR has a significantly wider field-of-view than the 17-50 OS. The difference is so large, in fact, that I believe the focal length of the Sigma is more like 18mm. That's quite disappointing. Of course, it also has significantly less reach on the long end, but that's expected. The Nikon most certainly wins here.
Time for some 100% crops. Center first, at their widest focal lengths and sharpest apertures.
The 17-50 is most certainly sharper in the center at 17mm. What about at the extreme edges?
The Sigma loses this battle. But what if we stop it down to f/8.0?
Getting better... but still not as good as the Nikon. At 50mm these lenses look virtually identical in the center. However, again, the Sigma loses sharpness in the very extreme corners. It's worth noting that only the most extreme corners are problematic with the Sigma. The non-corner edges look quite good, and the average sharpness across the frame is outstanding.
Verdict? This one is a draw. It comes down to this: do you prefer the Nikon's overall sharpness consistency over the Sigma's slightly sharper center and slightly worse extreme corners?
One advantage that the 17-50 OS does have, however is the f/2.8 constant aperture. This can make for some pretty decent portraits at (or around) 50mm.
The above photo is cropped a bit. If I had been standing a bit closer and had framed it properly, the background would look much more bokeh-licious (more blurry). Here's a 100% crop:
Sharp, and very nice. For comparison, I took this portrait a few years ago right after I got my 16-85 VR:
Also very sharp, and actually it's quite good. I had to stand further back and ended up with a tighter framing since I was shooting at 85mm. Both lenses do well here, but I'll give the edge to the Sigma since it has the faster aperture and a creamier look. I wish I had time during this review to take some better portraits. I may update this section in the future if I come up with anything better.
I want to love the 17-50 OS, but it just leaves a bit too much to be desired. Yes, the f/2.8 aperture opens up some great portrait options when used as a casual walk-around lens. The major downside for me is that the 17mm wide end is just too restrictive when compared to the 16-85 VR. That extra little bit makes a huge difference. The Sigma also has a few funny quirks: the zoom ring turns the "wrong" way compared to Nikon lenses, which is rather annoying. The OS works well, but seems to consume battery at a slightly faster rate than the 16-85 VR.
Sigma 17-50 f/2.8 OS PROS
- fast aperture (excellent in low-light)
- good construction (on par with the Nikon)
- excellent sharpness stopped-down (except the extreme corners)
- excellent center sharpness wide-open
- OS works well
- standard 77mm filter size
Sigma 17-50 f/2.8 OS CONS
- wider would be better (17mm seems more like 18mm)
- zoom action turns in the wrong direction (for Nikon users, it's hard to get used to)
- no weather-sealing (missing the butt-gasket, too)
- larger and heavier than the Nikon
- focus ring turns in AF mode (make sure those fingers are out of the way!)
Nikon 16-85 VR PROS
- excellent focal length range (16mm is wide)
- good construction
- excellent overall sharpness, especially in the corners
- VR works well
- lighter and smaller than the Sigma
Nikon 16-85 VR CONS
- slow aperture, especially at maximum zoom (bad in low-light)
- non-standard 67mm filter size
- no weather-sealing (although it has a butt-gasket to keep moisture from the lens mount area)
What do I really want in a fast-aperture DX "normal" zoom? A 16mm wide-end is a must. Excellent sharpness across the frame is a must as well. Finally, either a slightly longer-than-normal focal length (70mm on the long end) with a moderately fast aperture, or a very fast aperture and a shorter focal length (f/2 and 40mm).
For me, and I suspect for many others, either of these imaginary specs would be perfect:
- 16-70 f/3.5 (stabilized)
- 16-40 f/2 (stabilized)
If this rumor has any truth to it, we all may be in luck... but for now I'll probably stick with the 16-85 VR.
Full-Sized Sample Images
- Sigma 17-50 OS @ 17mm, f/8.0
- Nikon 16-85 VR @ 16mm, f/8.0
- Sigma 17-50 OS @ 50mm, f/5.6
- Nikon 16-85 VR @ 50mm, f/5.6
I'll leave you with one final image, taken with the Sigma @ 50mm, f/4.0: