Please be assured and perform following methods to resolve the Camera issue:-
1. Please clear data or cache of Camera Application(Tap Settings > Apps > Camera > Storage > Clear Cache/data).
2. Check device in safe mode - Using Safe Mode on a Samsung phone allows you to force the device to run the essential operating system, and disable most 3rd party applications. To enter in safe mode: Press and hold the Power key, when Power off icon appears>Press and hold the power off icon. To Exit safe mode: Restart the device.
3. Reset the Device :- Kindly create data backup of your device via SMART switch mobile application or http://www.samsung.com/in/support/smartswitch pc suite How to reset :- Settings>General Management>Reset
If the issue still persist, kindly register your concern in Samsung Members app (Samsung Members app > Get help > Feedback > Error report/ask question). Note: Please send device log files within 15 minutes of issue occurrence along with the exact issue details.
