A reader and landscape photographer, impressed by how well the 20 mm f/1.8 performs on the Nikon Z7, asked if he’d really be much better off with the Fuji 23 mm f/4 on a GFX 50x.
Let’s take a look, with the Fuji lens on a GFX 50R.
Here’s the scene, with both cameras at equivalent apertures:
Corner falloff is less with the Fuji.
Here’s the test protocol:
- Distance: 97 meters
- ISO 64 for the Z7, and 100 for the GFX 50R
- Manual exposure, ETTR in live histogram.
- Subject in the center and the lower left corner.
- Manual focusing.
- 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.
- Lens corrections undefeated.
- 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 282×218 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 Fuji images are slightly larger (317×246 pixels), since the Fuji sensor has a greater image height measured in pixels. I picked the crop sizes to hold crop image height as a percent of sensor image height constant across the two cameras.
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.
In the center at equivalent apertures:
The Fuji is more detailed.
In the lower left corner:
The differences are more striking in the corner.
That’s a pretty substantial difference.
The trend continues.
In this case, you get what you pay for. On the other hand, you can make quite nice landscape photos with the 20 mm Nikkor and a Z7.