Why dual camera in iPhone - it's great

As many manufacturers flagship devices already in full equip their smartphones dual camera, it seems clear that the Apple will follow the same path in the new iPhone. However, few people understand why dual camera.
In addition to improving the quality of the photos, dual camera owners of smartphones opens a new way to focus with the same name. Apple now practicing in the iPhone 6s and iPhone 6s Plus technology called "focus pixel": it uses a part of the pixels as a phase sensor. In fact, this is the usual phase autofocus, but in a nice wrapper Apple's marketers.
The phase detection autofocus is good? He will contrast and allows to estimate the motion of an object by means of sensors (AF tracking). However, its main drawback - not work properly in poor lighting conditions. And suddenly the camera is focused not on what you need to fix it would be quite problematic.
Dual camera with easily copes with the last task. Here to take clear pictures of the battle are just two of the lens - is one camera takes a picture of distant objects with fixed focus, the other does focus directly on objects nearby. Therefore, you can quickly take a picture, and then adjust the focus (in Lytro cameras, yes).
Changing focus
Yes, dual camera provides a less accurate focus than a phase, but it has an important advantage, which has already appreciated the owners of Honor 6 Plus smartphone from Huawei or the same HTC One M9 +. And if Apple how to work in this direction, you can hardly go back to the iPhone with a single camera.