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.
From Canon:
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
- An “overheat control” function to reduce heat generation when the camera is in standby
In regard to the installation of a fan: The decision not to install a fan within the body was made in order to maintain the EOS R5’s compact size, lightweight construction, and weather resistance.
Before recording starts, the EOS R5 and EOS R6 display an estimate of the recordable time based on the current camera temperature and the set recording mode.
Canon has published and included below the approximate recording and estimated recovery times for 23°C / 73°F environments and ensure that the camera will warn users when it is getting too hot. Additionally, tips to reduce overheating as well as recovering time are listed below.
Timing:
How can you reduce heat buildup in the EOS R5?
- Set Overheat Control function to “ON” (default). When the overheat control function is enabled, the movie size and frame rate are automatically changed while the camera is in standby mode to suppress the rise of the internal temperature
- Between recordings, it is recommended to turn off the camera
- Position the camera out of direct sunlight
- Use an external fan to dissipate heat
How long will it take for the camera to recover?
Estimated camera recovery times are indicated below. The time until full record time is available will vary with ambient temperature, continued camera operation, and the selected shooting resolution.

What about the EOS R6?
Like the EOS R5, the EOS R6 offers powerful movie recording and stills capabilities within a compact body design. At the highest frame rates and resolutions, heat is inevitably generated. We believe the EOS R6 offers the best in class performance, especially for enthusiast photographers and video content creators.
The EOS R6 can record up to the 29 minutes 59-second recording limit in the 5.1K oversampled 4K 60p mode at (23°C / 73°F) before encountering any heat-related issues within the camera and up to 40 minutes of 4K at 30p.
Canon need to manufactures an EF lens adapter with a fan to suck heat directly from the sensor for the long take video shooters.
I wonder how it would work if I had the camera on and taking photos here and there, and then switched to shot a short video
I've pre-ordered however, I find the heat issues a very dissapointing with all these limittions.
i second this as well as what happens if the ambient temp is warmer
Come on, that's crazy talk! We really want those long, boring YouTube videos to get longer and higher resolution...:)
Probably any vortex created between lens and sensor may degrade the image quality, because of different densities. The handheld photocamera form factor + weather sealing makes really difficult to dissipate heath efficiently.
But that means using only EF lens, right? I wonder, if they could solve it somehow from within the grip? There would have to be some metal part connection, to dissipate the heat though. There seems to be some strange part close to the hinge of the LCD screen. If it would be metal and not plastic, could serve the purpose with some additional tools. But what about an external recorder for such situations?
How is over heating effected with different ambient temps? from switching from stills mode to video?
How is over heating affected with battery grip?
How is heat affected when recording to external monitor? and whats the maximum external frame rate / resolution to external? is it oversampled?
EDIT: overheating is real:
I am usually very quick to criticize large companies who fail to meet expectations or pull some pseudo bait-and-switch nonsense, but I genuinely don't believe the outsized criticism of these heat "issues" is warranted. The R5 is not -- and was never advertised as -- a C500 replacement. The spec sheet, even including these high end recording limitations, is more than I possibly could have asked for 6 months ago. What were others who are more critical honestly expecting? (This is not a pejorative statement by the way, I'm genuinely curious -- if you're disappointed by this, what were your expectations?)