Helicon Remote is an excellent Android app for Nikon DSLR users as it extends the features and capabilities of the camera.
I wrote about extending the bracketing feature of your DSLR camera in this article, which is a great enhancement. Now, the developers have added yet another neat capability to this app. The new version of the app now allows shooting videos using your Android device.
According to the Google Play page of the app:
Experimental support for video recording (with live view) on Nikon D5100/D7000/D800/D4, Canon 1d Mk IV/5D Mk II/5D Mk III/7D/60D/500D//550D/600D/1100D. Shooting without live view is now possible on any camera if the preference "Disable live view during shooting" is set and the lens is in manual focusing mode. All Nikon cameras can save pictures to memory card in this mode.