Regarding the brightness changing on its own.

[Android Central Question]

Why when you walk into a bright room does the screen go brighter and vise versa, surely it should be the other way around?.

Going darker when you walk into a dark environment and brighter in a bright one is counter productive surely?.

 

[belodion]

The brightness of the screen has to compete with the ambient light, so will need to increase in light surroundings, and decrease in dark ones.

Auto brightness adjustment can be turned off if you prefer manual settings.

 

[B. Diddy]

This is exactly how it's supposed to work. If the screen dimmed in bright light, it would be much harder to see -- try it yourself some time by manually decreasing the brightness of the screen while outside in bright sunlight. And in dim light, it makes sense for the screen to dim -- otherwise, your eyes will be blasted by a bright screen (which can cause some degree of temporary night blindness, like shining a flashlight in to your eyes, and then trying to stumble around in the dark).

 

[mustang7757]

I like to add if your on pie you can train it how dim or bright in different lighting with the slider that way it knows how you like it, its called adaptive brightness.