Are bigger pixels less noisy?

Started 4 months ago | Discussions thread
gardenersassistant Veteran Member • Posts: 8,903
A comparison of ISO 100 with/without NR to ISO 8000 with NR
4

alanr0 wrote:

Nick Zochios wrote:

What i posted is an iso 8000, without any editing, from an old technology camera which is has a usable limit of around 3200-4000 (the most)

How do you define "usable limit" in this context?

Now at iso 8000, It has very little noise due to great software.
That's the fact. Either like it or not! (tbh i don't care

As far as I can tell, nobody is denying that noise can be reduced in software. There are questions as to how well it can be done without destroying texture and image detail, but we don't have anything to compare against at this stage.

I did a comparison test using the processing that Nick Zochios used.

Here is the scene.

I used a Sony A7ii with Sigma 105 macro using f/8, on a tripod using a 10 second timer and image stabilisation off. I captured two raw files, one using ISO 100 and one using ISO 8000. The raw files are available here at Dropbox.

I loaded the raw files into Lightroom. Apart from setting the white balance from the ColorChecker Passport, I made no changes to the default settings. This means that some sharpening was applied and some colour noise reduction, but no luminance noise reduction.

I exported the ISO 100 image to JPEG, using default output sharpening.

I exported both images to 16 bit uncompressed TIFF and used DeNoise AI with Auto settings.

Here are some comparison screenshots from Faststone Image Viewer at 100%, with the ISO 100 JPEG out of Lightroom on the left, the ISO 100 out of DeNoise AI in the middle and the ISO 8000 out of DeNoise AI on the right.

Comparison 1. The Lightroom JPEG looks softer than the DeNoise ISO 100 image, but the DeNoise AI has edge artefacts. These artefacts look minor compared to the noise-like artefacts in the DeNoise ISO 8000 image. See for example the bottom left patch of the ColorChecker Passport.

Comparison 2. The DeNoise AI ISO 100 image shows the weave all across the cushion. The Lightroom ISO 100 image shows some of the weave, less clearly. The DeNoise ISO 8000 version doesn't show any of the weave.

Comparison 3. The shadows don't look particularly noisy to me in any of the images. However, the large scale print on the right hand battery in the DeNoise ISO 8000 image  is extremely poorly rendered compared to the other two images.

Comparison 4. The issue with the weave is repeated. Much more striking though is the area to the left of the woman's eyes, where all detail has been lost in the DeNoise ISO 8000 image. The other two images both have a good amount of detail in that area.

Comparison 5. This comparison illustrates both loss of detail and, on the battery, noise-like artefacts, but it also shows a loss of colour in the reversed UK Pound sign and the surrounding dark area to the left of the Queen's head.

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