When I switch to video mode, something I don't use often, the view finder or view screen are much less bright and sharp compared to shooting in still mode. Is there a setting for this? Shutter speed is about 125, f6.3, daylight conditions, FDH mode. The brightness is like half of the still mode and the colors are more subdued than in the actual scene. I can't believe anyone shooting video would want to use this. Sometimes I see the message STANDBY LOW RES ON, but goes away. No idea what that means.
Thanks for any advice.
Turn off Standby Low Res mode in the menu. This mode when on, saves battery life and reduces internal camera heating during movie shooting but causes the issues that you are describing.
See this from the camera manual:
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.