To follow up on yesterday’s post about my initial impressions of the Nikon Z7 and 24-70mm lens, I’m including a number of additional sample photos and image quality crops in this article to answer some reader questions about how well the 24-70mm performs with the Z7. This includes vignetting comparisons versus the Nikon 24-120mm f/4 for the F mount, as well as 100% crops to test sharpness for daytime and Milky Way photography.
Keep in mind that all of the information below is simply a continuation of my first impressions for this camera and lens, and we are continuing to work on the more extensive reviews of all the Nikon Z equipment here at Photography Life. We have six copies of the Nikon Z7 and 24-70mm f/4 S lens shipping to us in total, and only one has arrived so far. Further examination may reveal issues with some copies of the lens that are not present in others, or perhaps extensive sample variation that alters our final review.
Milky Way Crops
One frequent request I received after posting an image of the Milky Way in the prior post was a crop and comparison versus ISO 6400. The following photo is the one in question, with the stars captured using an equatorial mount for an 860-second exposure at f/4 and ISO 64:
The image quality is, as you would expect, amazing. Click to see a 100% crop:
This is why you get a star tracker!
And here is a photo from the same night captured at ISO 6400 and 20 seconds, no equatorial mount. Keep in mind that this is taken with the Nikon Z 24-70mm f/4 lens – a focal length and aperture that are far from ideal for Milky Way photography. Even then, I found it impressive and captured a workable image as a result:
The 100% crop has nowhere near the level of detail that the other image did, but keep in mind that this is still very impressive performance considering the aperture and focal length involved. It’s also a good torture test of the Z7’s high ISO performance:
I also received a request to check the corners of this lens for coma and spherical aberration performance. Again, this isn’t the focal length or aperture I recommend using for star photography, but the 24-70mm f/4 is currently the widest angle native lens available for the Z7. So, here is a 100% crop (click to see full size) from the top left corner of the 860-second exposure, demonstrating the maximum definition you can achieve in the edges for astrophotography:
Yes, it’s pretty impressive, although keep in mind that it’s an f/4 lens. If Nikon manages the same lack of coma with an f/2.8 lens or wider (the 58mm f/0.95, perhaps?), that would be an even bigger deal.
One thing I noted in yesterday’s first impressions review is that the 24-70mm f/4 had very high levels of vignetting, to the point that I mistakenly thought the edges of my polarizer were in the frame at 24mm. I said that without having a direct comparison in front of me – and I had already corrected much of the vignetting in the sample photos I displayed – so a few readers justifiably asked me for a more specific comparison. I’ve now gotten my hands on a 24-120mm f/4 lens for the F mount, adapted to the Z7 via the FTZ adapter. In our review of that lens, we noted that it had high levels of vignetting throughout the zoom range, particularly at 24mm. Here is how the Z 24-70mm f/4 S compares to the F-mount 24-120mm f/4:
The worst vignetting performance of all eight images above is the new 24-70mm f/4 at 24mm, although the 24-120mm gives it a run for its money at the same focal length. At 35mm, the Z lens is decidedly worse than the F lens. At 50mm, the lenses are quite close in vignetting performance, and the question is whether you prefer the more gradual fall-off of the Z lens or the more sudden fall-off of the F lens (I prefer the Z lens, personally). At 70mm, the Z lens comes out slightly ahead, although neither is great.
In short, although the 24-70mm f/4 S is far from unusable because of vignetting, it is clearly a factor at f/4. Still, at least to me, vignetting is not the biggest optical problem a lens can have, since it is comparatively easy to correct in post-production.
24-70mm f/4 Sharpness
The 24-70mm f/4 S is an exceptionally sharp lens all the way out to the mid frame and edges. It is only the very extreme corners which are not best-in-class in sharpness. Again, this is my takeaway from shooting sample photos from the lens and not a result of our lab tests, which are coming up – but I still wanted to include some sample photos below to give you an idea of the image quality you can expect from the 24-70mm f/4.
Here is the uncropped photo, with a red box to indicate the crop I did at the edges of each photo (taken at each full aperture stop from f/4 to f/16):
You can click on each of the following crops to see a 100% view of that corner of the image.
See what I was saying about the unusual pattern of sharpness drop-off? Each of these crops has spectacular sharpness throughout 90% of the frame, and only the extreme corner – stretching from some of the aspens on the far side to bits of the grass – is blurry. Keep in mind that this isn’t due to the fact that the grass is nearer to me and out of focus, because the grass on the left-hand side of each of these crops is exactly the same distance from the plane of my camera sensor, and it is extremely sharp in every photo. (The only way the sharpness decrease here could be due to out-of-focus blur is if the 24-70mm has extremely high levels of field curvature, which is an issue in and of itself, and something we will test for in the lab.)
Still, you shouldn’t read too much into the comparatively blurry extremes of the photos above. The amount of blur is no different from what you’ll find on most good zooms out there, and many top primes as well. To me, the more interesting thing is how consistently sharp the 24-70mm f/4 is throughout the image, ignoring the most extreme corners. If you apply a 1.1× crop to the photo in post-processing, you’d think this was one of the sharpest lenses on the market, regardless of price or focal length range. In visual form:
I don’t want to make these results seem better than they are, so don’t take away that this lens is perfect. At the same time, this sharpness fall-off doesn’t conflict with my overall takeaway from the 24-70mm f/4 – that it is a very sharp lens. We’ll be testing it soon to determine exactly how it behaves at each focal length and f-stop, but I would be very surprised if it doesn’t rank among the sharpest zooms we have ever measured.
Also, although this test was only at one focal length on the 24-70mm f/4 (specifically 45mm), I’ll point out that I noticed the same behavior throughout the zoom range. Look forward to more in-depth tests in our final review.
Flare and Sunstars
For landscape photography, two oft-overlooked features that make a good lens (and camera system overall) are the amount of flare and the quality of sunstar/starburst effects. I am happy to report that the Nikon Z 24-70mm f/4 S is very good in both respects, and the Nikon Z7 has impressively low levels of the annoying red dot flare problem often found on mirrorless cameras.
Take a look at this photo, with a very bright sun at the top of the frame. The only flare to be found are two small green dots to the upper left of the sun – not an issue at all:
And the quality of sunstar effect is excellent:
If you’re worried about the vignetting at f/4 or the sharpness fall-off near the extreme corners of the 24-70mm, maybe this will convince you that it nevertheless is a very impressive lens! Personally, I’m planning to use it as my main landscape photography lens for the foreseeable future, at least for the standard focal lengths.
Z7 First Impressions Article Updated
I added a few more notes to the Z7 impressions review from yesterday, including a bug that affects image review on the rear LCD, and further coverage on the inability of the Z7 to remove shooting icons from the LCD when shooting in live view.
Hopefully these crops and sample images helped you understand a bit more about the behavior of the Nikon Z7 and the 24-70mm f/4 S lens. I am particularly impressed by the low amount of red dot flare on the Z7, along with the overall impressive optical characteristics of the 24-70mm f/4. Keep an eye out for our upcoming reviews of the Nikon Z7 and 24-70mm f/4 lenses, along with the 35mm f/1.8 S (which is on its way to us for testing right now). And again, if there is anything you’d like us to test on the Z7 or 24-70mm as we continue to test them, just let us know below.