Inside I prefer that it is as low as it will go if I am in the dark, and in a lighted room up to 20%. Outside in sunlight, up to 50%. My eyes are pretty sensitive to light. If I go too bright, I get immediate headaches.
Biggest problem. I switch brightness levels often, and going from as low as it goes to outside I cannot see the screen in sunlight at all to be able to change the settings.
Biggest problem. I switch brightness levels often, and going from as low as it goes to outside I cannot see the screen in sunlight at all to be able to change the settings.