Bring up an external Camera on Android device and use its display to view the live feed from the camera

USB On-The-Go , or USB OTG, is essentially a female USB port that plugs into the Micro-USB port of a phone or tablet, allowing you to connect devices that use a standard USB 2.0 or 3.0 connection. In a nutshell, the adapter allows the Android device to be a "USB host," powering and communicating with the connected device.