Sony fuses their best pocket digital camera technology from the Sony DSC-RX100M II into your iOS / Android device and calls it the QX100.  Benefit?  Well you use your phone's internals with the awesome sensor so you get the best instagram pics!

Sony DSC-QX100 Smartphone Attachable Lens-Style Camera, Carl Zeiss 3x f/1.8 Lens, 20.2MP

It will set you back $498 though.