I ran into this issue when shooting in the cold (around 0 degrees and lower) where the C300 III turns on, can record, but all that is captured is this white to purple gradient with black diagonal bars that move slowly. From my tests audio is not recorded and the only way to fix the issue is to bring the camera into a warm place. That said, I have had mixed results preventing and resolving this issue - any help would be greatly appreciated!
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
04/20/2023: New firmware version 1.4.1 is available for EOS R3
03/30/2023: New firmware updates are available.
2/07/2023: New product announcements!EOS R8 EOS R50RF-S55-210mm F5-7.1 IS STMRF24-50mm F4.5-6.3 IS STMRF15-30mm F4.5-6.3 IS STM