I don’t know if this is already been properly answered but I have the same problem and I have figured out that when you switch to 2X zoom it’s switching the actual camera to the digital zoom camera and cam that advances the focus and the depth…, which is the camera on the right when looking at the back. So for some reason the main camera is not working, but the secondary camera/zoom camera for some reason Works fine.. I am waiting on a warranty replacement, as this is my fourth iPhone 7 Plus that I have had replaced, Luckily not with the same exact problem. I’ve been talking to Apple and really want a solid answer because with all of the above, it’s not the board, or anything. It has to be the camera itself, my guess something to do with the advanced auto focus and gyro-stabalizer.