Night mode is an automatic setting which takes advantage of the new wide-angle camera that's in the iPhone 11 and 11 Pro models. It's equipped with a larger sensor that is able to let in more light, allowing for brighter photos when the light is low.
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Teardown Suggests Apple Watch Series 5 Components are Close to Identical to Series 4
That should come as no surprise as the two devices are identical in design, with the major differentiating factor being the Always-On display in the newer model.
iFixit hoped to get a look at the changes implemented to allow for the Always-On display, but much of what's new relates to display technology and is "invisible to the human eye."
The site did spot a new ambient light sensor embedded under the OLED panel, and Apple says there are more advanced display drivers and an improved power management chip in the Series 5 as well.
There's a new built-in compass and the battery is slightly bigger than the battery in the Series 4 (1.4% larger in the 44mm model). The Series 5 chip includes 32GB of storage, up from 16GB, and the new compass, but it features the same GPU and CPU as the Series 4 so there are no real performance improvements.
iFixit says there are minor changes to connectors for the Taptic Engine, display, and battery, which means components are not generally interchangeable, but otherwise, the two devices are "very similar" on the inside.