Hello, somatimes bad things happend to camera. even if using untouched ImageTargets example.
Sometimes in initialisation procees of camera QCAR just gets zero size for camera preview. Resulting in black background in application.
Log in console: Configure Video Background: Video(0,0), Screen (1280,752), mSize(0,752)
This happened to me on Asus EEE Pad Slider SL 101 (ICS), and on asus EEE Pad TF300 (on ICS stock rom and on Jelly Bean Stock rom too)
So i tried to restart device. Didnt helped.
Clearing application data and application cache didnt helped even.