Last night, I was using the video camera on my 5s and taking a few short movie clips. When I was finished, I switched to different apps and continued using the phone intermittently in the next 2 hours. The camera app had stopped recording but was still in the task switcher and was on video mode. So approx 2 hours later, I was surprised to find I had drained about 30% of my battery. The phone felt slightly warm even it was sitting mostly unused on the couch. So went to Settings-> General->Usage->Battery Usage and found that the Camera app had consumed a substantial percentage. Also, it was labeled as "Background Activity". Nice to have this iOS 8 feature to track what's eating up battery. Does this mean the Camera continues to function (I.e focusing, setting expore,etc) while it is inactive but still in the task switcher? There is no option to turn off background refresh on the camera app. Next time I have to remember to force quit the camera app, or not to leave it in video mode in the app switcher after use.. Has anyone have this happened to them before?