Shortly after Canon released the EOS R5 and R6, reports started surfacing that the cameras could overheat recording video. No Film School first reported about this during the initial release of the cameras and as a reason why we disliked the camera. However, it was based on written information instead of real-world testing, but does the overheating actually matterwill you ever run into it as a problem?

As of July 14, 2020, No Film School doesn't know of anyone, either with press or content creators online, that have a production model of the Canon R5 or R6. If you do have one, let us know in the comments below. 

Videos from Canon ambassadors, or even dealers who sell the product used pre-production models. Why is that important? Pre-production models are not the final versions of the camera and can, and often do, see changes before they make their way into consumer's hands. This could potentially handcuff those "reviewing" the cameras in what they can actually share as fact. That last word is important. Fact. Not thoughts. Not opinions. Actual facts that can be tested and reported on as actuality or not. Since the release, more information has become available directly from Canon. 

Below is the statement from Canon in its entirety:  

"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 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.


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 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."

What does this all mean? 

The biggest question is how the potential overheating affects workflow and filmmakers. To be clear, it will take real-world testing to find out. There's no easy answer at the moment as production models of the camera are not available yet. Yes, Canon has provided suggested record times, but how does that translate in a real setting. How does it affect a filmmaker's workflow? Where in a cart before the horse moment. It's very similar to RED's Komodo camera. There's a lot of information available but not everything.

That said, you can still look at certain things to see if the camera potentially fits into your workflow. If you simply only understand math, you can begin to recognize that the limited record times on the Canon R5 and R6 may not be an issue.

For example, let's look at the storage capacity needed to record 8K. A 256GB CFexpress card provides approximately 13 minutes of 8K RAW recording. Then you need to change out the card. 512GB about 25 minutes, which is close to the 20 minute maximum record time. Again, then you need to change the card. How much do those CFexpress cards cost? Between $400 and $600. 

Are filmmakers rolling for 20 minutes straight? Sure. See David Fincher. But Fincher's budget is going to be different than yours. He's going to have multiple cameras on set that are exchanged out immediately. 

If you want to bump the CFexpress card to 1TB, which provides approximately 51 minutes of record time, that will cost you between $600 and $1,000 depending on the model and write speed. Even with that 51 minutes of record time, it's unknown exactly how the R5 or R6 could potentially overheat. Is it 8K for 20 continuous minutes only? Is it shooting 8K for 20 minutes over an hour? Over 4 hours? At what temperature does it start to overheat? Is it immediate when shooting above 73°? How long are the actual waiting times? And many more questions are still unanswered at the moment. 

What is known is that when shooting to an external recorder the cameras will not encounter overheating issues. The only contention is the limitations of the storage device on the recorder.

Additionally, 4K video recording on the R5 potentially overheats when High Quality mode is turned on. This High Quality mode oversamples the sensor at 8.2K or 7.7K, depending on the frame rate, and outputs the 4K image. When High Quality mode is turned off, recording time is not limited by heat. With the R6, the sensor oversamples 5.1K to produce its 4K image, and with certain frame rates, it potentially overheats. 

For now, this is to be continued, but at least Canon released an official statement for those considering a pre-order. No Film School will be testing exactly what is happening under the hood when production models do arrive.