Recently my 4s has started to act strangely. At least 1/2 dozen times the phone has turned off when I press the shutter button on the camera. I turn it back on and then take a picture without it turning off. So, at worst this is intermittent. However, it should not be happening at all. Any idea what is going on? The phone is around 2 1/2 years old and has worked almost flawlessly until now. Of course, it is out of warranty. I have never dropped it and the case is protected. Outwardly, it is in excellent shape.