Lens Sharpness and Contrast
While the previous generation 24-70mm f/2.8G is a wonderful lens overall, it has a couple of serious optical flaws, such as a wavy field curvature, which when focused in the center quickly degrades sharpness in the mid-frame and the extreme corners of the frame. In fact, one can observe sharpness dropping significantly in some areas outside the center frame, then coming back again. Such optical flaw is clearly visible in Nikon’s MTF charts at the shortest focal length (observe the wavy nature of the blue lines on the right chart, which belongs to the Nikon 24-70mm f/2.8G):
Although Nikon certainly attempted at fixing the field curvature with the new optical design, it is still there. As you can see from the left chart, there is a drop of sharpness in the mid-frame, then the sharpness comes back towards the edges of the frame. It is certainly a lot less noticeable though, especially once you stop down a little.
Looking at the above chart, one can notice that Nikon shows superior optical performance from the center all the way to the edges of the frame. Keep in mind that such MTF charts are mostly simulated and the data is simulated for focusing at infinity. As you will see below, focusing on a subject at close distances shows a completely different picture.
Zooming in towards 70mm, we can also notice changes in the MTF graphs (Left: Nikon 24-70mm f/2.8E VR, right: Nikon 24-70mm f/2.8G):
Nikon promises a much more even performance across the frame compared to its predecessor, although we can see that the older 24-70mm f/2.8G certainly did better in resolution slightly outside the center frame. However, the edges are where we see huge differences – take a look at how sharply downward the curve goes on the old 24-70mm f/2.8G and how it stays high on the 24-70mm f/2.8E VR. This basically shows that Nikon made significant changes to the lens design and the corners should be looking a lot better now compared to before.
Now the big question is, do the above MTF charts actually match lab and field tests? To answer this question, we will first take a look at some Imatest numbers. Here is how the lens looks at 24mm:
The Nikon 24-70mm f/2.8E VR starts out very strong in the center, with visible drop in mid-frame and corner sharpness due to field curvature. Once stopped down to f/5.6, it shows excellent overall performance.
Let’s see how the lens does at longer focal lengths:
At 35mm, there is a slight drop in sharpness at large apertures in the center, but the mid-frame and the corners still stay impressively good. Interestingly, stopping down does little to increase the extreme edges of the frame, as they already look very nice!
Similar to the Nikon 24-70mm f/2.8G, the 24-70mm f/2.8E VR also starts to take a hit when zoomed in. As you can see, we observe an overall drop of sharpness at 50mm, with the center area taking the biggest hit. There is visible sombrero field curvature at the widest aperture. Stopping down to f/5.6 brings the center sharpness back, which becomes the sweet spot of the lens.
And lastly at 70mm, the lens suffers even more in terms of sharpness at maximum aperture. Stopping down to f/5.6 again yields the best result, although the corners don’t look as impressive as they looked earlier.
Now what do the above numbers correspond to in the real world? Let’s take a look at four different images shot at f/2.8, f/4.0, f/5.6 and f/8, roughly @ 35mm, infinity focus (Left: f/2.8, Right: f/4.0):
And stopped down (Left: f/5.6, Right: f/8.0):
All of the above crops are 100% crops without sharpening or lens corrections applied to them. As you can see, aside from differences in vignetting, the image at f/2.8 is only slightly less sharp than the image at f/4. Starting from f/4 all the way to f/8, the corners look pretty much the same. Now that’s a huge achievement on behalf of Nikon if you ask me! In fact, the Nikon 24-70mm f/2.8E VR does better in the corners than many other prime lenses!
Overall, the sharpness performance of the new Nikon 24-70mm f/2.8E VR is very impressive. Compared to many other similar-grade lenses, the 24-70mm f/2.8E VR produces much more even, balanced results across the frame.
The above numbers might not make much sense, since there is no reference data to compare with. For this reason, I would strongly recommend that you check out the Lens Comparisons section of this review!
In terms of contrast and colors, the Nikon 24-70mm f/2.8E VR is a top-class performer. The images are vivid and beautiful, definitely the signature of pro-level lenses.
Lenses like the Nikon 24-70mm f/2.8E VR are typically not optimized to yield beautiful background highlights and the presence of aspherical lens elements makes things even worse, because aspherical glass often causes ugly onion-shaped bokeh. Overall though, bokeh on the 24-70mm f/2.8E VR looks pretty decent when the highlights aren’t too bright:
Keep in mind that while the out of focus areas look good wide open, if you were to photograph bright lights in the background, the highlights might not look this pretty. If you want pretty bokeh, I would recommend using a dedicated portrait lens instead, such as the Nikon 85mm f/1.4G.
The previous generation Nikon 24-70mm f/2.8G showed a pretty heavy amount of vignetting at the shortest focal length of 24mm, getting better at longer focal lengths. Let’s take a look at how the new Nikon 24-70mm f/2.8E VR does in comparison:
Looks like the new optical design not only did not address the vignetting issues – it made them worse. As you can see, there is a pretty significant amount of vignetting at all focal lengths when shooting wide open. Stopping down, however, drastically reduces vignetting and once you are at the f/5.6 mark, you only need to take care of the darker corners at 24mm.
Here is the worst case scenario, showing rather strong amount of vignetting at 24mm in the extreme corners, infinity focus:
In all honesty, vignetting is not a big concern. I often do not touch vignetting exhibited by a lens, since I like how it draws the attention of the viewer towards the center of the frame. Every once in a while, however, I will remove vignetting in post-processing software, which can be taken care of with a single click.
Ghosting and Flare
The Nikon 24-70mm f/2.8E VR is equipped with Nano Crystal Coat, which certainly helps in reducing flares and ghosting. Shooting against the sun might result in some flares and ghosts showing up in your images, so do not be surprised to see them when pointing your camera towards the sun, or any other bright light source. Keep in mind that the amount of ghosting and flare will depend on where the bright source of light is in the frame. For example, if you put the sun towards the extreme edges, you will most likely see those artifacts. If you carefully place your light source in the frame, you might have no ghosting and flare to deal with.
And if that becomes an issue, check out my article on how to remove ghosting and flare in images.
Let’s take a look at how the lens handles distortion:
As you can see, barrel distortion is rather heavy at 24mm, which then transforms to pincushion distortion at 35mm and then gets stronger again between 50 and 70mm. I personally do not worry about distortion problems on my lenses, because they are very easy to fix in Photoshop and Lightroom. In fact, Lightroom already has a lens profile for the Nikon 24-70mm f/2.8E VR, which is nice, since all you have to do is check “Enable Profile Corrections” under “Lens Corrections” and all distortion will be automatically removed from your images, as I pointed out in my Lightroom Lens Correction article.
Chromatic aberrations are pretty strong at wide focal lengths and gets to lower levels at 70mm, as seen below:
Still, it is a bit disappointing to see that the new Nikon 24-70mm f/2.8E VR does worse than its predecessor when it comes to CA. Lateral chromatic aberration is particularly worst at 35mm. Again, chromatic aberrations are easy to fix in post-production and Lightroom can easily take care of it in via Lens Corrections.
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