Image Sensor and Banding Issues
Although the Nikon Z6 has a very similar sensor as found in Nikon’s D750 and D610 cameras, its performance characteristics are slightly different by comparison, as you will see in the ISO performance and “Camera Comparisons” page of this review. One difference is that the Z6 has phase detection pixels included on the sensor. These do have a negative effect on the overall image quality, but only by a very small, perhaps unnoticeable margin.
Due to the nature of phase detection pixels, the sensor is going to be potentially prone to some line pattern issues (which others have also referred to as “banding”). This has become a normal thing to see on most modern mirrorless cameras with phase detection pixels, although the issue has been associated disproportionately with the Nikon Z6 and Z7 based on some of the first reviews of these cameras. Basically, when heavily underexposing in particular lighting conditions, or when shooting against very bright sources of light, the camera can exhibit visible lines in some parts of the image.
How bad is this issue? To be honest, having shot several thousand images with the Nikon Z6, I am yet to encounter an image where I notice any problems with line patterns/banding. While I was able to reproduce patterns of lines when shooting a test target in a dimly lit indoors environment, I have not seen a single image that I shot in the real world where banding was a problem, even when I had to really recover a lot of shadow detail. Take a look at the following images from the Nikon Z6, Sony A7 III, Canon EOS R, and Nikon Z7. These photos were underexposed by an unreasonable six stops, way more than you would ever do in reality, and even then the banding issue is hardly even visible:
To my eyes, the Nikon Z7 has the least banding, while the Canon EOS R has the most. The Nikon Z6 and Sony A7 III are on par with one another, with perhaps a slight edge to the Sony. However, keep in mind that this banding is only visible with extreme shadow recovery, and you are unlikely to see any of it in practice.
The images above also serve as a good comparison for shadow recovery and dynamic range. The worst performance of the bunch is the Canon EOS R, with flat shadows and excessive color noise. The Nikon Z6 has much less visible noise, although it also has a green color cast which is not ideal (even if it is largely fixable in post-processing). The Sony A7 III does not have this color cast while matching the Z6 in noise performance and shadow detail, so it is the better file here. However, the best performance comes from the Nikon Z7, which is the sharpest file with the lowest noise – by far the most shadow dynamic range of the four cameras, largely because it has base ISO 64 rather than 100.
The above is covered in our detailed Nikon Z banding issues article.
Highlight Dynamic Range Comparison
Now that we’ve examined dynamic range and noise patterns in the shadows, what about highlight recovery? This one is more important to everyday photography, where photographers often blow out bright details in the sky or other highlight regions and try to fix things in post. The following images were overexposed by three stops over the meter’s recommendation, then darkened to be equal in brightness. Again, the comparison shows the Nikon Z6, Canon EOS R, Sony A7 III, and Nikon Z7 in that order:
The cameras all struggle with perfect detail recovery in the brightest highlight regions. However, they are all about equally bad, with only the Canon EOS R appearing significantly worse than the others (see the yellow color swatch, which is very faded in the Canon image). The Nikon Z6 is perhaps a hair worse than the Sony A7 III and Nikon Z7, which are essentially identical to one another in highlight recovery capability. That is impressive on the Sony’s part, since the Nikon has a lower base ISO of 64.