Have you managed to sort it i updated yesterday and same thing has happened to me contacted apple support who told me to go into store as it may be the sensors yet i know its due to this update.. went in the guy did factory resets and a normal reset and then in the end quoted me £75 to change the rear camera even though i explained its not a hardware fault otherwise why would my front facing stop working in the apps ive updated aswell so it was working on instagram since updating to ios and then doing an insta update the front wont work yet works for face recog facebook and the actual camera rear and flash work for nothing