@Members_dayR78B: I'm not sure what could be causing this. Can you try heading to Settings > General Management > Reset > Auto Restart At Set Times, and make sure that this is toggled off. If it is, and if the issue persists, then restart the phone in Safe Mode and monitor the performance for a few hours, depending on the frequency of the restarts. If you notice an improvement, restart your phone as you would normally, and delete any recently installed 3rd party apps. To enter Safe Mode, press and hold the Power button until the 'Power off' prompt appears on the screen then release > Touch and hold Power off until the 'Safe mode' prompt appears then release > To confirm, tap Safe mode.
@Jul03: For clarity, is the viewfinder not showing an image, or are your resulting pictures black? As a basic troubleshooting step, try heading to Settings > Apps > Camera > Force Stop > Storage > Clear Cache > Clear Data, then restart your phone. If the issue persists, open the Phone app > Dial *#0*# into your telephone keypad > Select Megacam from the series of tiles. If the issue is present here then there may be a problem with the hardware, therefore please reach out to our Help Desk via the link below, where an advisor will be able to arrange for the device to be inspected by one of our engineers.
