It takes two: A visual history of dual-camera mobile phones

With the recent launches of the iPhone 7 Plus and the LG V20, the dual-lens smartphone camera is once again a hot topic. Of course, many other companies will want to remind you that they were there first, except some have long since given up on the technology. So what happened? And why isn't this yet a standard feature on all flagship smartphones? For those intrigued, it's worth taking a trip seven years back in time.