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.
If the issue still persist, kindly register your concern in Samsung Members app (Samsung Members app > Get help > Feedback > Error report) along with screenshots, short videos and error log file, so that we can assist you accordingly.
Note: Please send device log files within 15 minutes of issue occurrence along with the exact issue details.