Dual camera systems on smartphones have been around for several years now. Some of the earliest examples include the weird 3D camera on the HTC EVO 3D. Then it was HTC again who introduced it in a different form on the One m8. Then LG decided to drop in with its cool wide-angle lens with the G5 and the same year, Apple decided to take in the other direction by adding a telephoto lens on the iPhone 7 Plus. Meanwhile, Huawei had other ideas, with its Leica branded monochrome camera on the P9. But just how many types of dual camera systems are out there and how do they differ from each other?...
Source: http://www.gsmarena.com/understanding_the_dual_camera_systems_on_smartphones-news-27516.php
