Apple is known for their high quality hardware, but a series of tests done recently show that the sensors of some iPhone 5S models are miscalibrated.
Gizmodo conducted the tests on two separate iPhone 5S units show that the units are giving inaccurate measures for the device’s level, accelerometer, compass and gyroscope. These tests compared the iPhone 5Ss to those of the iPhone 5 and a number dedicated tools measuring these things. The iPhone 5S’s readout was found to be 2-3 degrees off in leving calibration compared to a Stanley spirit level. Other users have reported that it was as high as 4-6 degrees off. The iPhone 5, however, was exactly the same as the level.
The gyroscope function did a little better. The iPhone 5 showed the expected 0-degree readout when set down on a table. The iPhone 5S was –3 degrees off. In the compass test, the iPhone 5 was far more accurate in identifying magnetic north than the iPhone 5S.They were consistently 8-10 degrees apart from one another. The iPhone 5S accelerometer registered more latent motion than its predecessor as well.
They note that the testing is far from conclusive, but these aren’t the only tests that are being done on the new handset. But it isn’t all iPhone 5S. Some users have taken them back to exchange them and have no further issues.