I have recently dug up my old camera (D610) as I wanted to do some performance comparison with my new camera, the Z 6 II. I will have a few comparison posts coming and this will be the second one of the lot (the first one you can see here).

Now there is significant ISO differences between the D610 and the Z6II. To start, the D610 has a maximum ISO of 6400 (not counting the “high ISO” setting) while the Z6II has a maximum ISO of 51,200 (again, not counting the “high ISO” setting), which is 8 times the maximum of the D610.

This leaves me puzzled, as I often have issues with the photos that I would take that would require an ISO as high as 6400 in the D610. How will the Z6II perform at ISO 6400? Even more: are photos at ISO 51,200 even usable (without serious noise reduction)?

I ask this question mainly because I don’t like the results I get when I’m trying to reduce the noise from photos with low light/high ISO. To clarify this question, I decided to put the ISO to the test.

The test below I’ve taken the same photo with my D610 and Z6II at ISO 6400 and asked the cameras to: 1 – no high ISO noise reduction, 2 – normal high ISO noise reduction. The photos were taken with 50mm, f/9 and shutter speed to 1/200. To highlight the issues with noisy photos, I increased in all photos the exposure by +2.66 and shadows by +58 in Lightroom.

It’s quite visible the difference between the Z6II and the D610. The Z6II takes a lot more exposure and shadows increase to show noise at ISO 6400. The images of the Z6II do look darker and lose a lot of detail to the blacks (if not increased above what I have) and the D610 are more magenta and more yellow. Overall, the Z6II photos hold well together.

For the second part of the ISO testing, I will use only the Z6II for higher ISO tests. I will go to the highest ISO setting without going into the “high ISO” configuration. Again, to highlight the issues with noisy photos, I increased in all photos the exposure by +2.66 and shadows by +58 in Lightroom.

It is clear that the high ISOs (51200) introduced a lot more noise to the photos and, like with the 6400 ISO, the normal noise reduction (due to low light) did not have a significant affect on the results. In the image it is easy to see that when increasing the exposure and shadows that much, a “fish eyed” mesh becomes visible. As such, I will avoid using such a high valued ISO whenever possible, or avoid increasing the exposure through Lightroom. Unlike the D610 in 6400, the colors of the Z6II at such a high ISO setting did not introduce magenta tones to the photos, only yellow tones.

In summary, the 6400 ISO of the Z6II is better, but requires a higher adjustment in Lightroom to be able to see the introduced noise. With the 51200 ISO in the Z6II, despite de added noise, it performs quite well.