Ah, but your in MY House now, says the Mac.
@Eternal28 & Others.
It just occurred to me the expectations you have, vs. the designed intent. This not withstanding, I still have issues as will others, with tough lighting situations. (Tough for the designed intent)
You expect the backlight to turn ON when its dark? and OFF when its Light. Right?
Ennng. Wrong.
Thats not how this 'hyper-intelligent' obtuse system works. (Sometimes too-smart to work right, if you ask me.)
Look, why would the backlight DIM when you put your finger over the sensor? Because Apple is thinking:
Case A: Sensor: Whoa ! It just got Darker, therefore we need LESS backlighting to compensate and make it visible, but not glaringly bright. This mode may piss you off, if the sensor is getting light, but the keyboard is not... damn it, not enough backlighting.
Case B: The opposite also: Sensor says: "It's pretty bright out there, I need LOTS of backlighting to illuminate the characters with sufficient CONTRAST. This mode may piss you off, if you want it OFF during the "daytime."
Case C: Sensor: "It's so damn bright out there I'm going blind, and no one shouldn't be able to see the Keys, without ANY backlighting. This mode shouldn't piss anybody off.
The reality is that without a diffuser over the light sensor, (which is inset and damn tiny, probably shared with camera), and given its necessary "LCD-plane" location, it is next to impossible for it to make the right decision in all lighting circumstances, which vary FAR MORE widely than an engineer can account for with 100% effectiveness.
Doesn't it suck to say: "Well, they did their best..."?
When the "Illuminate keyboard..." Pref is checked you're saying: Here, Mac, why don't you control everything, turn it ON, turn it OFF, adjust it for me, 'cuz damn, obviously I don't have the brains (or attention) to do it all myself. While you're at here's some stocks I need trading.
Sound like a Mac? Sho 'nuf.
The reality is though. Sometimes we just want the damn thing ON, or OFF. When it's dark, when its light. Suck an egg, Mac.
That's not something their switches allow. Picky, picky engineeroids.
How's that for more than you wanted to think about light sensors.?
Sef.