Nikon Z 17-28mm f/2.8 Focus Speed and Performance
The Nikon Z 17-28mm f/2.8 autofocuses quickly and almost silently, with very impressive accuracy both in the viewfinder and in live view. This is as much due to the camera as the lens, but it’s still great to see the trend continue on the 17-28mm f/2.8 considering that it’s a Tamron-designed lens.
Because of the f/2.8 maximum aperture, the Nikon Z 17-28mm f/2.8 focuses in very dark conditions quite well. Compared to an f/4 lens like the 14-30mm f/4 S, the 17-28mm f/2.8 can autofocus in conditions with half as much ambient light. This not only makes it a good choice for Milky Way photography, but also for blue hour lighting conditions, or even for using a neutral-density filter during the day.
In terms of manual focus, I still have my gripes with focus-by-wire systems, but I can’t complain too much considering that almost every autofocus lens these days (not just from Nikon) uses focus-by-wire. At a minimum, however, I recommend updating your Nikon Z camera’s firmware to allow linear manual focus if you haven’t already. In my experience, linear manual focus makes it much easier to focus on difficult subjects like the stars at night.
Lastly, the close-focusing capabilities of the Nikon Z 17-28mm f/2.8 are pretty good, with a maximum magnification of 0.19× when you’re at 17mm. (This decreases slightly to 0.17× when you zoom into 28mm.) At this magnification, the front of your lens will be just a couple of inches away from your subject, so it’s not practical for a lot of shots. Still, I found it fun to use this lens to photograph the patterns in a frozen lake up close, and I was glad that the focusing distance of the lens didn’t limit me. Ultra-wide close-ups definitely have their place in photography.
The Nikon Z 17-28mm f/2.8 has surprisingly little distortion for an ultra-wide zoom, although the limited zoom range is a bit reason why. Here’s a full chart of the distortion I measured in the lab throughout the focal length range:
As you can see, the greatest distortion is actually found at 24mm and 28mm, where it reaches about 2% pincushion distortion. In a very unusual feat for an ultra-wide zoom, the widest focal length of the 17-28mm f/2.8 has less than 1% barrel distortion. Here’s a simulation of that distortion at both extremes:
For context, the Nikon Z 14-30mm f/4 S has some of the highest distortion I’ve ever seen outside of a fisheye lens, maxing out at 7.89% barrel distortion at 14mm. Meanwhile, the Nikon Z 14-24mm f/2.8 S has 3.52% barrel distortion at the most, also at 14mm. Even the Nikon Z 20mm f/1.8 S has 1.94% barrel distortion! So, the Nikon Z 17-28mm f/2.8 is seriously impressive in this regard.
That said, for many photographers, your post-processing software will remove distortion by default, so you’ll never see any curved horizons or bubbly buildings anyway, regardless of your lens. This is true of Adobe Lightroom, for example, where there is a non-removable lens profile on the Nikon Z 17-28mm f/2.8.
In uncorrected images, the Nikon Z 17-28mm f/2.8 has fairly high levels of vignetting wide open, although for an ultra-wide zoom, it’s about as expected. The level of vignetting is worst at 17mm, and close focus is a hair worse than infinity focus. Here’s a full chart of the vignetting levels I measured in the lab:
The maximum of 2.16 stops of vignetting comes at 17mm and close-focus, but 17mm and infinity focus is basically the same at 2.14 stops. (For a lens like this, vignetting at infinity is much more important in general.) The vignetting levels gradually improve as you zoom in and stop down, but even at their best, you’re still getting about a stop of vignetting with this lens.
By comparison, the Nikon Z 14-30mm f/4 S maxes out at 2.51 stops, which is actually worse, although it improves drastically upon zooming in. The Nikon Z 14-24mm f/2.8 S reaches 2.05 stops of vignetting at the most and remains slightly ahead of the 17-28mm throughout the focal length and aperture range. Finally, even though the Nikon Z 20mm f/1.8 S has 2.01 stops of vignetting at its worst, it’s already down to a mere 1.27 stops of vignetting by f/2.8 – so that lens is the clear winner of the bunch.
To me, anything more than 2 stops of vignetting is fairly high. 1.5 stops is usually not a problem, whereas 1 stop and under is negligible. By that metric, the Nikon Z 17-28mm f/2.8 has moderate vignetting overall. Granted, vignetting is correctible in post-processing, but doing so exaggerates the level of noise in the corners of your photos. High vignetting can be a problem for something like Milky Way photography – which is otherwise a strength of this lens.
Also, if you’re a Lightroom user, keep in mind that Adobe Lightroom’s lens profile for the Nikon Z 17-28mm f/2.8 directly reads information from your in-camera vignetting reduction setting. If you want your photos from this lens to have full corrections by default, you need to turn the vignetting correction to “High” in-camera. This is true even if you’re shooting .NEF files. It’s not a big deal because you can always add or remove vignetting manually, but I recommend turning the in-camera corrections to “Medium” or “High” to minimize your post-production work.
There is a small to moderate amount of lateral chromatic aberration on the Nikon Z 17-28mm f/2.8. It’s worst at the wide end of the focal length range but negligible at 28mm. Here’s the chart:
As you can see, stopping down improves the chromatic aberration performance slightly, and it never reaches extreme levels anyway. By comparison, the Nikon Z 14-30mm f/4 S reaches 1.72 pixels of lateral CA at the most, so the two lenses are very comparable. However, both the Nikon Z 14-24mm f/2.8 S and the Nikon Z 20mm f/1.8 S perform better, maxing out at 0.92 and 0.85 pixels of CA, respectively.
Anything under about one pixel is almost impossible to notice in real-world images, even with chromatic aberration corrections turned off. I didn’t notice any meaningful amount of CA in my real-world photos with this lens, even with something like a tree against the sky.
The Nikon Z 17-28mm f/2.8 is sharper than I expected, even though it’s not at the level of Nikon’s best. Here’s how it performs at 17mm in my lab tests:
Although the f/2.8 corners and midframe could be better, this is a standard, solid performance already. Taking the whole frame into account, the sharpest aperture at 17mm is f/5.6, although I wouldn’t hesitate to use any of the other apertures (aside from f/16 due to diffraction, which is present on all lenses). Considering that most landscapes at 17mm have a nearby foreground, I frequently found myself at f/8, f/11, and, yes, even f/16 when shooting with this lens.
The overall performance is about the same at 20mm, although f/2.8 looks better at least. The corners and center don’t improve much when stopped down, although the midframe does get better and peaks in the f/4-5.6 range. Still a good performance overall.
24mm is an improvement over the wider focal lengths, and it’s arguably the strongest focal length on the Nikon Z 17-28mm f/2.8. From f/4 to f/8, the performance of the Nikon Z 17-28mm f/2.8 remains high in the corners, midframe, and center. The mild dip in midframe sharpness at f/5.6 is due to field curvature, which has a slightly different shape at each aperture, and at f/5.6, happens to overlap with where I extract the “midframe” results from Imatest.
The performance at 28mm is rather interesting, because it’s pretty weak at f/2.8 (especially in the corners) but gets much sharper as you stop down. 28mm and f/4 has the sharpest central result I tested, although the corners are still weak at f/4. Stop down to f/5.6 or f/8, however, and the corners get much crisper.
So, whether the sharpest focal length of the lens is 24mm or 28mm depends on your aperture, not to mention the part of the frame you care about the most. In any case, the lens performs well overall in terms of sharpness – even though you’ll see on the next page of this review that it’s not Nikon’s sharpest ultra-wide lens.
In terms of other sharpness issues, there is a bit of focus shift on the Nikon Z 17-28mm f/2.8. It’s relatively minor, however, and you can easily work around it by stopping down your aperture first and then focusing. The issue is not significant after f/4. As for field curvature, it plays a role in the lens’s performance, more so at the longer focal lengths. You may need to stop down a bit extra to make sure that your depth of field intersects with every part of your composition. Still, I’ve seen worse.
Related to sharpness is coma, a lens aberration that can make dots of light in the corner of a photo look like smears. Coma isn’t usually visible in everyday photography, but for something like Milky Way photography, it can be a factor. Considering that a 17mm f/2.8 lens is a good choice for Milky Way photography, I wanted to put the Nikon Z 17-28mm f/2.8’s coma performance to the test.
Here’s the image that I’m cropping from, for context:
This tiny 637 x 956 crop is a direct excerpt from the Nikon Z7, taken at 17mm and f/2.8:
As you can see, there is practically no coma at all. You can safely use this lens for Milky Way photography!
Sunstars and Flare
Ultra-wide lenses commonly have a lot of flare, but surprisingly, the Nikon Z 17-28mm f/2.8 bucks the trend. It certainly isn’t flare-free, but you’ll get less of those distracting ghosts and discolorations with this lens than most. Here’s a typical example with the bright sun in the frame:
Not bad at all! Usually, ultra-wide lenses would have more flare than this. But despite the Nikon Z 17-28mm f/2.8’s relatively high number of lens elements (13), it maintains good contrast in backlit situations like this and adds minimal flare.
That said, I should note that the Nikon Z 17-28mm f/2.8 has a tendency to pick up small dots of flare even when the sun is far outside your frame. Make sure to use the lens hood with this lens at all times, and you’ll minimize the issue.
As for sunstars, I got excellent 18-bladed sunstars with this lens, especially at f/16. You can see a bit of that in the photo above, but it gets even better when the sun is partially covered by something like the horizon or a cloud:
Overall, I couldn’t ask for better flare and sunstar performance than this, especially considering that we’re talking about a zoom. This is definitely one of Nikon’s best Z-series lenses when shooting in backlit situations.
Spencer: Not bad. I was expecting worse performance than this on a non-S zoom.
Nasim: Relatively speaking, sharpness is the lens’s weakest point, but I still see it as good. There’s not a focal length or aperture that I would avoid for lack of sharpness, or for any other reason.
Spencer: Before I tested it, I was wondering how the 17-28mm would handle Milky Way photography. I had hoped for slightly better vignetting performance, but the almost complete lack of coma is excellent. Definitely a good candidate for star photography.
Nasim: But not the best of the bunch! I’d still rather have the 14-24mm f/2.8 S or the 20mm f/1.8 S for photographing astro-landscapes.
Spencer: You’re talking about small differences here. I shoot Milky Way photos with my 14-30mm f/4 all the time, no problem. Good technique and image stacking can take you far.
Nasim: Not as far as f/1.8 :)
The next page of this review dives into the sharpness numbers a bit more, with some comparisons against other lenses that Nikon users may be considering. So, click the menu below to go to “Lens Comparisons”:
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