This is the third in a series of posts about the Nikon 70-200 mm f/2.8 S lens for Nikon Z cameras. The series starts here.
So far, I’ve found out that with the Nikon 70-200 mm f/2.8S there’s about the same amount of light falloff wide open at 200 mm as there is with the similar E lens that’s made for the Nikon F-mount cameras. I’ve also found that I have a good copy of the Z-mount lens. I had previously tested the F-mount version, and it is good as well.
Now I’m going to show you the results from an informal comparison of the two lenses using distant foliage as the subject with both lenses set at 200 mm, which is usually the weakest focal length with a 70-200. Here’s the view with the S lens wide open:
Here’s the test protocol:
- Subject distance: 97 meters
- ISO 64 for center shots, ISO 125 for corner ones
- Manual exposure, ETTR in live histogram.
- Subject in the center and the upper right corner.
- AF-S focusing, so as not to have to deal with the terrible Z7 focus by wire algorithm.
- Three shots at each setting, focusing anew for each shot, picking the best. This method calibrates out focus curvature.
- Developed in Lightroom
- Sharpening set to amount 20, radius 1, detail 0, which is quite a bit less than Lr’s default sharpening.
- Daylight white balance
- Adobe Color Profile
- Minor exposure adjustments, with same adjustment applied to all images from both lenses, so corner darkening is unaffected.
- Chromatic aberration correction turned off.
- Everything else at default settings
We’ll look at some tight crops.
If you’ve seen these here before, just jump to the images. If not, I need to spend some time telling you how to interpret them. They’re at roughly 250% magnification, enlarged to 700 pixels high on export from Lightroom. If you just want a rough idea of the differences, just look at the images as displayed in-line in the posts. However, if you wish to compare these images in detail, you should view these images by clicking on them to see the source files, then set your browser for 100% zooming. Even better, download them and make Photoshop stacks.
No matter what you do, these crops are all going to look horrible. I’m blowing them up so much so that they will represent the original file after JPEG’s discrete cosine transform has had its way with them. If you want to get a good idea of what the images would look like printed, get far away from your monitor. No, farther than that. Put a bunch of the images up on the screen and back up until the best one starts to look good. Then look at the others. There’s another reason why these images won’t look like the best thing the camera/lens combination can deliver. They’re demosaiced with Lightroom. Lightroom is not awful, but for a particular image, there are usually better raw processors. I use Lr because it’s a de facto standard, because I know it well, and because it’s got good tools for dealing with groups of images.
Here’s how to use these highly-magnified crops. The dimensions of the Z7 sensor is 8256×5504 pixels. If we make a full-frame print from the Z7 on a printer with 360 pixels per inch native driver-level resolution, like the Epson inkjet printers, we’ll end up with a 26.4×17.6 inch print. The 317×246 pixel crop you’re looking at will end up 0.8×0.68 inches. Let’s imagine that you or your viewers are critical, and will look at the 27×18 inch print from about 18 inches (conventional wisdom is that the distance would be a little greater than that, or 28 inches (the diagonal), but you did buy a high-resolution camera for a reason, didn’t you?).
The next step is dependent on your monitor pitch, which you may or may not know. Turns out, you don’t have to know it. Just take the 250% crops and view then at 1:1. How high are they? Get out your ruler and measure, or just guess. Let’s say they are 6 inches high. 6 inches is about 7 times 0.8, so in order to view the crops the way they’d look from 18 inches on the print is to view them from 7 times as far away, or 10.5 feet.
Everything here scales proportionately. If the image on your screen is bigger than 6 inches, increase your viewing distance by the ratio of your image height to 6 inches. If you think your viewers are going to almost get their nose to that print and look at it from six inches, divide that 10.5 feet by 3, and look at the image on the monitor from three and a half feet away.
Both of those are excellent, and they are very similar.
It is amazing to me that both these lenses are virtually as sharp on-axis wide open as they are stopped down one stop.
This is probably the sharpest stop for both lenses, and they are both very crisp here.
In both cases, diffraction has adversely affected the images compared to the f/5.6 ones more than reduction of aberrations has improved them.
More diffraction softness yet.
Well, that was impressive. Let’s look at the corner. Image brightness is consistent within the corner shots, but they have different brightness than the center ones.
The biggest difference is that the E lens has substantially more lateral chromatic aberration (LaCA) than the S lens.
There is still some LaCA in the F-mount lens at f/4.
Still a little LaCA on the E lens.
That LaCA is still hanging around with the E lens. Fortunately, it’s fairly easily dealt with in post-production.
Still a bit of LaCA left with the E lens.
Looks like these are both great lenses. I’ll do some testing with a Siemens Star, which is a more demanding target.