At night (in the dark), everything you see has fluctuating intensity. This is change in the number of photons that you detect - when there are few photons, the number of photons per second per detection cell noticeably fluctuates, and you can see that, easily.
At night (in the dark), everything you see has fluctuating intensity. This is change in the number of photons that you detect - when there are few photons, the number of photons per second per detection cell noticeably fluctuates, and you can see that, easily.
Change in the number of photons and noise from your wetware.
But yeah, it’s pretty neat that our peepers have a built-in gain system