I recommend you clear the camera app cache firstly
@pc1901, which can rid your camera of any erroneous behaviour that is has picked up. To do this, simply go to your camera app icon on your home screen and press and hold it until a grey information tile pops up. Press the small circled i symbol at the top right of this tile which takes you to a page of options. Scroll down and select Storage on this menu. A sub menu now pops up with a Clear The Cache option at the bottom right. Press this and wait for the cache to fall to O in this sub menu before returning to your home screen. I would now reboot your device and see if the problem has been cleared. Good luck to you.