Consider the following video:
This was recorded with a Panasonic X1. Those containers were around 400 meters away; I was zooming all I could, but I was only using the optical zoom, not the digital one.
You'll see that there is a certain area of some of those grey containers which appears very noisy. The video has been compressed with a quite low bitrate; I can assure that in the original video it was much worse.
Normally I'd think that's because of the gain, but in this case there was zero gain. I tried to play with the iris and the shutter, but it stayed the same. I checked all the various settings I could think of, but nothing changed, except when I set the knee master slope to zero, in which case the noise was reducing itself a little, and when I set it to 100, where that gray became even noisier.
I'd like to know why it gets so noisy. Maybe you have an idea?
Consider it was quite of an hot day (around 28°C) and that noisy part seems like it was made with little reflective foils. It's possible that the air was hot enough to create those tipical optical distortions, which, given the distance, were maybe creating a continous series of hyper-illuminated dots, which ended up being perceived as noise by the camera. This might explain why I was having some success playing with the slope. But I don't know, this just looks like a whole lotta noise, not like hot-air optical distortions.