I would say it is a trait of the breed. Since they are Livestock Guardians, they are sort of constantly on guard-even when sleeping. I think eventually Bear will sleep through things such as you walking past, and the everyday sounds associated the your household. Now, when there is an unusual sound (such as the sound of the camera, or a knock at the door), Bear will most likely wake up.
Basically what I'm tryin to say is, once Bear gets used to his surroundings, he won't wake up at the drop of a pin UNLESS it is an unusual sound-something that doesn't happen everyday.
Am I making sense? I sure feel like I'm rambling, and I still can't get out what I'm trying to say. hahaha