The Dual feature allows you to take a picture or record video with the front and rear camera lens at the same time. A smaller image window overlays the main image (similar to picture-in-picture). You can resize and move the overlay image window, as well as swap the lens for either view.
From the Home screen, tap Camera .
Tap the Mode icon > the Dual icon .
Drag the overlay window to move it where you want it on the screen.
Touch and hold the overlay window to resize it.
Tap the overlay window to switch its lens.
Tap the Capture button to take a dual photo.