There has been a lot of concern recently about how the Canon EOS R5 and Canon EOS R6 handle heat when recording 8K and 4K video. Canon has released an official statement on the issue.
Details Regarding Canon EOS R5/EOS R6 Overheating During Video Recording
The EOS R5, one of the latest additions to Canon’s full-frame mirrorless camera line, offers class-leading autofocus with high-resolution and high frame rate video recording options using the maximum width of the full-frame sensor at high bit rates. Inevitably, this combination of features has the potential to generate some significant heat, which will limit recording time.
Canon has taken several steps to manage the potential for overheating, including:
Magnesium alloy was used in the body to dissipate heat away from internal components