[matthiasv]

> Sometimes it's better to take a deliberately underexposed photo and tweak regions of it in post to achieve the desired exposure instead of introducing global noise from in-camera amplification.

That is definitely not my experience for Canon's in low light situations. Here [1] is an example shot at ISO 100 but pushed by 5EV to match the brightness of the same scene shot at ISO 3200. The noise is much more tolerable for the latter.

[1] https://imgur.com/a/Ca9ccbK

P.S.: it's raw, no in-camera JPEG denoising in place.

[martomi]

Perhaps what we're seeing here is that quantization errors for the non-amplified signal become larger than the noise introduced by the amplification?