Thanks for your trying on this all-black scene, I talked to dahua , without any fill light, the gain will be pulled to a highest level, the problem of white DOT on the sensor side will appear, this can be handled by the software, but it will affect the clarity of the general scene. Because this all-black scene is rare, it is not recommended to modify it. So can remove the dot, but will effect the normal pic badly.
So in the nighttime when light situation is not good, the gain will increase a lot to make the pics as best as they can, this dot actually will be found on all cams, why before ones not easy to find? Because most of them use IR, black and white, why 4K easier to watch? Because it's using the 4K with 1/1.2cmos, we get the best pics compare to those 2mp or 4mp cameras.
So that is why daytime you will never see those dot.
@looney2ns place has very low light, so i always test low light capacity at his place, so he found the dot can explain why.
These full color cameras has big improvement compare to the old camera tech, but still need light to offer the best full color pics. And
@wittaj post the light to max, most place not really need the strongest light if you are not at deep dark place, if has some light around the camera led will not even will turn on.
I try to do some testing and prove the findings.
1. Warehouse is in bit low light, light even can't see the face 6ft far away, You see the left upper corner not dot, it's big white blocks,-------The camera's LED light was shut off.
View attachment 144051
2. LED light on, so you see the left upper side, things much better change. But when we digital zoom, still find some dots nearby the light. ------Camera LED light on.
View attachment 144052
3. I open warehouse light on.
View attachment 144056