MacBook Pro keyboard backlighting loses current setting? I recently bought the 13" MacBook Pro and using the function keys set the keyboard backlighting to be four steps below the maximum setting, as indicated by the graphic that appears on the screen. Often when I boot the computer or open the lid after a sleep period, if I adjust the backlighting by one step then I notice that it has a noticeably different value to what I set it to. For example, it might have dropped from near the maximum value to the half way setting.

Is this normal behaviour of the Mac adjusting the backlighting level for the ambient lighting conditions? Or should the on screen graphic retain the same number of bars regardless of whether I'm outside in brilliant sunshine or in a darkened room?
Yes, it actually is normal. If you are in a well lit room, then the backlighting will refuse to turn on. 

So no, the onscreen graphic would not retain the same number of bars unless you stay in the same room or do not change into different lighting environments.