A method is set forth for automatically adjusting screen and keypad brightness on a mobile electronic device having a light sensor, display screen and keypad, for optimum legibility under varying lighting conditions, with minimal eye strain and distraction. The method includes obtaining light level samples from the light sensor, and independently adjusting backlight intensity of the display screen and keypad responsive to the light level samples. Preferably, correct screen and keypad adjustments are made responsive to pulling the handheld device out of its holster notwithstanding non-optimal ambient light detection while the device is being removed from the holster. According to another aspect, the described method allows for ambient light detection in a handheld device where the light sensor and a message notification indicator share a common light pipe.