If you are experiencing a black screen with your iPhone 5S camera, follow these steps to troubleshoot and potentially resolve the issue:

1. Check Camera Lens: Make sure that there is nothing obstructing the camera lens. Dust, fingerprints, or even a case could block the lens, causing a black screen when you open the camera app - learn more.

2. Force Restart the Device: This can clear minor software glitches. To force restart your iPhone 5S, press and hold both the Home button and the Power button until the Apple logo appears, then release both buttons - learn more.

3. Switch Between Cameras: Tap between the front and rear camera options to see if switching resolves the issue. Sometimes, toggling can refresh the camera functionality - learn more.

4. Check for Software Updates: Ensure that your iPhone is updated to the latest version of iOS, as software updates often fix bugs that might be causing camera issues. Go to Settings > General > Software Update - learn more.

5. Disable VoiceOver: If VoiceOver is enabled, it might interfere with camera functionality. To disable it, go to Settings > Accessibility > VoiceOver and toggle it off - learn more.

6. Close and Reopen the Camera App: This may help if the app didn’t launch properly. Double press the Home button to bring up your app switcher, swipe up on the Camera app, and then relaunch it - learn more.

7. Reset Settings: If the issue persists, you can reset all settings. Go to Settings > General > Reset > Reset All Settings. This won’t delete your data but will revert your settings to factory defaults - learn more.

8. Inspect for Hardware Issues: If none of the previous steps work, the problem may be hardware-related. It's advisable to consult with an official Apple service provider for a professional diagnosis - learn more.

By following these steps, you should be able to identify the cause of the black screen issue with your iPhone 5S camera and take appropriate action to resolve it.