How do Apple Mac computers adjust screen brightness?

How does the Apple Mac computer adjust the screen brightness? In fact, this is a very simple question, but see there are many Mac users are asking this question, today's small series also take out a tutorial alone, teach novice Mac users how to adjust the brightness of the screen.

1, in fact, look closely at the Apple Mac notebook keyboard, or the imac with the Apple Bluetooth keyboard you should be able to find the answer, F1 above marked with brightness of the small icon, meaning the brightness of the lower button, F2 above marked with a larger brightness of the icon, meaning the brightness height button.

2, if not, then with the left lower corner Fn key to try, FN+F1 is to adjust the brightness, fn+f2 is to adjust the high brightness.