A patent application reveals that Apple is working on an innovative two-sensor camera system for mobile devices. Unlike some two-sensor concepts focused on 3D image capture, the intent of Apple's design would be to provide robust optical zoom capability. In a nutshell, both camera units would capture the same scene at different focal lengths simultaneously. This would result in both a wide shot and closeup taken of the same subject, which could be stored together on the mobile device.
Current and past iPhones feature digital zoom, which utilizes software to simulate a longer focal length. One of the drawbacks to digital zoom is that photos can look grainy or pixellated, since the field of view exposed to the sensor never actually changes. Optical zoom would improve on this method, by placing higher magnification lenses between the subject and the image sensor. In a two-camera setup, the zoom unit would be capable of capturing a closeup at the same resolution as the standard camera.
Illustrations in the patent application show a live viewfinder with both the visual field from the standard camera and the zoom camera on the same screen. This would allow the user to view and frame a shot while seeing both focal lengths and how they capture the subject at the same time.
While the iPhone camera has historically been a primary focus for Apple, there is no telling if they plan to deploy this technology in future iOS devices. Typically the company will produce many prototype designs before a finished product sees the light of day in a public setting. Apple has already been granted a long list of patents that have not yet seen production.Patently Apple describes the patent application in detail, and also explains how the zoom system could be used with a gaming controller. For the complete application, see US patent application number 20160007008, Mobile Camera System, dated January 7, 2016.