If you are experiencing a very dark or completely black image display, even though the frame rate appears normal, please follow these steps to troubleshoot and resolve the issue:

1. Switch to Manual Exposure Mode
   Set your camera to manual exposure mode, then increase the exposure duration to allow more light to reach the sensor.
2. Check Lens Aperture:
   Ensure the lens iris (aperture) is open and correctly adjusted to allow sufficient light through.
3. Capture a Single Frame:
   Instead of using continuous image acquisition, try capturing a single frame to help isolate any issues with exposure settings or light capture.
4. Adjust Auto Gain Settings:
   If your camera has an auto-gain feature, adjust it to enhance brightness. Increasing gain can help in low-light conditions but may also add noise, so find a balance that suits your needs.

If the issue persists after following these steps, further investigation may be required to assess any potential hardware or software configuration issues. First of all refer to Bandwidth article.