Why can't my iPhone 5s take pics?

This has been going on for a few months now, I haven't even bothered to take it to Apple yet, and please don't ask why, but does any one know why this would happen, because none of my cameras work, not even my snapchat camera or my Instagram camera, every time I open up a camera in one of my apps it just shows black, and it also won't let me take videos either but how ever it will lets me FaceTime, but I just think it's really weird

Try resetting your settings! It won't delete anything

Check the settings for those apps. Perhaps you didn't allow them to use the camera