The camera monitor brightens when the DC coupler is connected.

When using a DC coupler (DC-C1, DC-C2) connected to the camera, depending on the camera model, the camera monitor's brightness may be fixed at maximum level and cannot be adjusted.
If the monitor's brightness becomes an issue, try the following methods that avoid using the rear monitor:

• For models with a vari-angle LCD monitor: Close the monitor and use the viewfinder (if available).
• For models with a viewfinder: Select VF (Manual) under Select Finder/Monitor, and set it to display images only on the finder.
• Connect to an external monitor: Turn On under HDMI Info. Display, then configure the settings so that images do not appear on the camera monitor.
• Use your smartphone as a display: Pair the camera with your smartphone via the Smartphone Connection feature.
  Notes:
  • Close the vari-angle LCD monitor when using the smartphone display.
  • To connect to a smartphone, you need to install the Imaging Edge Mobile or Creators' App mobile application.