For a reason that is best known the Apple designers and engineers the new range of iPod Touch 5s do not have the ability to auto adjust their brightness to match their environments. This bit of wizardry is achieved using an ambient light sensor inside the device, but this has been dropped from the newest design leaving professionals and consumers scratching their heads.
How Ambient Light Sensor Works :
By auto adjusting the brightness of the screen , the device reduces the battery consumption , improves visibility and even reduces stress on your eyes when reading in dark/bright environment .
Unfortunately this is not a mistake as it is clearly stated (or should that be NOT stated ? ) on the Apple website that the new iPod Touch does not have this feature.
Although no one has yet to find out a reason for this omission the complete overhaul of the iPod Touch design could mean that Apple just wanted to make the device more like a music player and less like the iPhone, because, let’s be honest, in looks the only difference was the thinness of the iPod over the iPhone.
Pure speculation; the real reason is no doubt one of a more technological nature, perhaps due to lack of space within the device or, similar trouble to the problems they had installing the sensor in the iPhone 4 white edition. A quote from a review of the iPod Touch 5 reads :
I also noticed, and this is a hardware issue as well, that these is no more Auto-Brightness setting in the Settings app. On closer examination, it appears that Apple removed the ambient light sensor from this year’s iPod touch.
I know that Apple reportedly had problems incorporating the ambient light sensor in the first white iPhone 4, causing numerous delays to that product. Perhaps the thinness of this device, coupled with the white face on all of the color models prompted Apple to forgo the feature.
Maybe this is the reason and to ensure an on-time launch they omitted it completely. Unless Apple themselves tell us, though, we will probably never know .