Why are there concentric circles from the light source (rendered in Blender)?

Question

Blender

I changed all the light sources (I didn't try only the "Sun" source, because it is not included in the task), set the sampling to 2048, changed the color depth of the PNG output format from 8 to 16, but still the program renders the light from the source on objects not with a smooth gradient, but steps/concentric circles.

What else needs to be done so that there are no steps of light on the objects?

Answer 1

Show the geometry (grid) of the object to begin with? I suspect that you have it like that, stepped.
I googled this topic, found that it is called Color Banding.
https://developer.blender.org/T59899
Unfortunately I did not find a specific solution, but now you have something to google =)

Answer 2

I see your steps. I'm sitting at a laptop that has a full hd matrix with an average range of color values.
I assume your monitor is the same. It's not a blender, but a display matrix. If you turn the brightness of the image up or down, steps will appear even on cool monitors.