iPod Touch 5G Doesn't Have an Ambient Light Sensor
The ambient light sensor is the part of an iOS device that allows the device to sense the lighting conditions around you and adjust your screen brightness accordingly. Unfortunately, it appears that the ambient light sensor is not present in the iPod touch 5G according to a report.
points out that after attempting to use Apple's new iPod touch outside, the device's screen brightness failed to adjust itself automatically, making it impossible to see what was on the display while outside.
Taking a look at the tech specs of the new iPod touch on Apple's Web site (shown below), it does appear that Apple has indeed removed the ambient light sensor feature from the iPod touch 5G’s sensor part of the site under tech specs for the device. Checking back with the specs of the iPod touch 4G, the sensor is present in that list.
Further supporting the report, Apple has removed the auto-brightness feature from the brightness options in the Settings application on the iPod touch 5G, while it remains present on the iPod touch 4G:
It's currently unknown why Apple went with the choice to remove the sensor, but it may have been necessary for fitting all of the new technology in the iPod touch 5G and keeping that slim form factor. Then again, it may not have been.
For some people that have auto brightness turned off all the time, the change might not be a big issue. It also won’t be a big issue for anyone that loves turning their brightness all the way up and hated how auto brightness might dim the brightness in certain conditions. For others, where the auto-adjustment was important, it’s going to be quite an annoying loss, as it will require you to visit the brightness options manually each time.