Or point out the problem in the examples that I posted above, because I don’t see it.
I have to agree that your samples are very uniform. I see nothing wrong with that noise, and if preserved in that way after "reasonable" edits then I'd be happy to hand if off as final work.
But, you mentioned the use of DXO and it has a reputation for achieving nice outcomes. What about pre-DXO? What about RAW?
In general Canon has been continuously working to improve their noise, which is why in part the higher ISO values become more usable. I'm not sure where in the pipeline that noise is adjusted or refined (if refined, depending on the model), but I wouldn't be surprised if Canon uses their a) knowledge of the sensor, b) knowledge of the lens behaviour (DLO data), and C) a pipeline to make a final trained-AI adjustment to the noise in the image. That could be done as part of generating the RAW image (a phase 1 adjustment to the sensor read) and in generating a DLO-derived TIFF, HEIC, or JPEG (a phase 2 output image adjustment as part of the DLO system). If any part of that is, in fact, true then that would go a long way to explaining the stellar VCM performance in the example image graciously provided by
@neuroanatomist.
To
@zardoz's point, I have witnessed myself bad artifact generation / deterioration when boosting aspects of an image and making other nudges (like correcting a building perspective). So I know it happens in scenarios, and when I first saw
@zardoz's post it made sense to me that the noise might be presented in a manner that would lend itself as described. But, I don't own an image circle compromised lens (in the physical sense) so without driving to my local store and grabbing some test photos I can't see it for myself (and I don't generally trust Internet posts on these topics these days).
But if it would otherwise happen in the VCM world then Canon or DXO is doing a bang-up job of creating a final image that hides the issue to some reasonable degree. If that same process would generate a TIFF or DNG for use in other apps, either via Canon's software or a direct import by, say, Photoshop then bravo to Canon for going the extra step!