Photographic Experiments at high ISO Settings - ISO16000

ISO16000 Out-of-Camera

I did some tests to study the ISO behavior of my camera (Z5 II + 50mm f/1.8 S) at really high ISOs. The reason is the often repeated claim that high ISO does not matter anymore. I want to know how much high ISO I can handle, and what should I set as maximum. Currently, I stay below 1600 for almost any scene. But maybe I can go higher with the modern tools if needed for fast shutter speeds.

Some readers may not be familiar with "exposure" and "ISO". The short explanation is that exposure is the light per area on the sensor. It is determined by the exposure time and the f-stop as set on the camera, ignoring light loss in the lens or filter. If you expose darker than the sensor can handle, because you need a short shutter speed or do not have wide enough aperture, you "under-expose". To fix such a dark image, higher ISO is used which will brighten up the image. Unfortunately, the unavoidable noise will also be brightened. The point of these experiments is to see if we can fix that problem with noise reduction.

Above you see an OOC image, exported as JPG and parsed through Lightroom because I wanted a 16:9 format and a look that does not blow out the ball and has a bit of light in the background. That is ISO16000 with the default noise reduction of the camera. I also made sure that sharpening is at 40% for the import and export of a sharpened image. Otherwise the result will be softened. I made the image warmer and added a tiny bit of contrast.

You will notice a bit of remaining noise if you zoom in. That is quite impressive, considering the noise you get in comparison from a RAW file with only minimal noise reduction. Below is a 100% zoom and you see the RAW with the minimal noise reduction (5%) on the left. There is far less noise in the overall image than you'd expect, but it is quite prominent when you zoom in.

For comparison, below is an ISO100 image. It is clearly much cleaner and easier to work with. If possible it is still preferable to use a low ISO. The image will handle better and more easy in post. The point is, that correct exposure is not always possible. We might want a high shutter speed to freeze action or camera shake or we might simply have not enough light for the lens we use.

ISO100

Can we fix the ISO 16000 in Lightroom so that it looks as good as the ISO100 version? 

For this, I used the new denoise tool and added a bit of noise reduction with the slider on top. We see a 100% zoom of the background. The result is almost exactly the same.

Here is another spot. I think, we can fairly say that it is possible to fix that noise in Lightroom for this type of scenes.

Here is the complete image at ISO 16000, noise reduced in Lightroom.

ISO16000 with recent Noise Reduction in Lightroom

Of course, this scene does not contain fine details besides on the ball. So, let us take a scene which is more difficult, like the deco below. It was almost in darkness in a light, where I would not dream of taking a picture if not for a test. I had to enhance the shadows a lot to make the details visible too. The aperture was f/5.6 and we are again at ISO 16000. I would say that the result is quite usable in an emergency where you really cannot get more light to work with. Feel free to zoom in using the viewer.

ISO16000

How about the same image at ISO100? I added a flash for more light to get the result below. Aperture is the same, but I seem to have focused a bit further.

ISO100

In direct comparison:

Have I learned something? I don't know. But here is my takeaway:

• Photos at ISO 16000 can be quite useful, even the default camera noise reduction is used. If you parse the RAW through Lightroom and apply the best tools there, the photos can be indistinguishable. That is especially true if you view at normal sizes.
• Good processing is necessary for the best results. OOC is close enough for smaller prints or screens.
• Blur due to camera movements or incorrect focusing are way more common ways to spoil an image than high ISO.

Note, that for APS-C cameras, the image above should be at ISO 8000 for comparison, and an aperture of f/3.5 instead of f/5.6. The Christmas images at the start can only be mimicked if you have a 35mm f/1.2 lens. On the other side, you might as well take a longer lens and get the same background blur.