I had the camera error restart camera message and rebooting and force stopping did nothing. I had an idea to try resetting the flashlight because the camera and flashlight seem to be connected somehow. I was able to get my camera working by going to the settings and turning my flashlight on and off. At first my flashlight would only stay on for 6 seconds or so but after turning it on and off through the settings screen it stayed on permanently. I then tried my camera again and it worked. I think the camera and flashlight on the droid turbo are linked somehow because of the functionality to open them by moving your hand and this causes them to freeze up sometimes. I hope this helps.