Too Hot To Handle? The Canon R5 Heat Check

It's a matter of physics. 

When Canon started confirming the specs of the R5, a full-frame mirrorless camera capable of recording uncropped 8K in 12-bit RAW, what didn't come to fruition until after its release was record limitations due to potential overheating. Canon followed up the initial announcement with a statement that detailed the video formats affected and approximate times for how long it would take for the camera to recover. 

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No Film School was provided with a production model of the R5 from Canon. Below are the results after testing the record limitations due to overheating under different conditions. The tests were conducted in NTSC mode. 

R5 Record Modes 

A quick overview for those who don't have the camera in-hand. The R5 has different record modes that include options for Canon's Log gamma curve and HDR PQ for high dynamic range shooting. For the sake of clarity, we're not going to label each record option with its corresponding bit-depth, chroma sub-sampling, and bit rate. Instead, only resolution, codec, and frame rates will be addressed to make it easier to follow along. 

Just know:

• 8K RAW is 12-bit 
• Canon Log and HDR PQ files are 10-bit 4:2:2 H.265/HEVC
• Non-Log/HDR PQ 8K files are 8-bit 4:2:0 H.265/HEVC
• Non-Log/HDR PQ 4K/Full-HD files are 8-bit 4:2:0 H.264/MP4 AVC

So note: in order to record internal 10-bit 4:2:2, Canon Log or HDR PQ must be enabled. RAW is always 12-bit. 

Normal Mode

Normal mode does not have any high frame rates, crop modes, or oversampling modes. It uses the full-width of the sensor which is 45MP and 36 x 24mm. These are the resolutions and frame rates: 

• 8K DCI RAW, 29.97/24/23.98p
• 8K DCI ALL-I/IPB, 29.97/24/23.98p
• 8K UHD ALL-I/IPB, 29.97/23.98p
   
• 4K DCI ALL-I/IPB, 59.94/29.97/24/23.98p
• 4K UHD ALL-I/IPB, 59.94/29.97/23.98p
   
• Full-HD ALL-I/IPB, 59.94/29.97/23.98p
• Full-HD IPB Light, 29.97p

4K HQ Mode

Canon's 4K HQ mode oversamples the sensor in either 8.2K when recording 4K DCI or 7.7K when recording 4K UHD. The 4K HQ mode must be enabled to be activated, and when it is, the word "Fine" reads below the record format. 4K HQ mode is not available in crop modes or when shooting higher frame rates. 

• 4K DCI Fine ALL-I/IPB, 29.97/24/23.98p (8.2K oversample)
• 4K UHD Fine ALL-/IPB, 29.97/23.98p (7.7K oversample)

  

Crop Mode 

Crop mode, as the name suggests, crops the sensor to APS-C, but it still oversamples the sensor to record the image. 4K DCI is oversampled at 5.2K and 4K UHD is oversampled at 4.8K. 

• 4K DCI ALL-I/IPB, 59.94/29.97/24/23.98p (5.1K oversample)
• 4K UHD ALL-I/IPB, 59.94/29.97/23.98p (4.8K oversample)
   
• Full-HD ALL-I/IPB, 59.94/29.97/23.98p
• Full-HD IPB Light, 29.97p

High Frame Rate Mode

Canon includes a high frame rate mode for 120p. High frame rates are not oversampled or are available in crop mode. 

• 4K DCI/UHD ALL-I, 119.9p 

R5 overheating icon is circled in red

What Video Formats Potentially Overheat

Knowing the formats, below are the resolutions and frame rates that are limited in record time due to potential overheating. Canon has provided suggested record times, but they are not dogma and only should be used as a general reference.

Depending on your climate and memory card type, you can expect different results. When the camera starts to overheat, an icon will start flashing on the screen. If you continue to use the camera it will automatically power off and shut down. The R5 displays: "Overheating! Shutting Down." 

Normal Mode 

• All 8K options no matter the resolution or frame rate. This includes RAW, Log, HDR PQ, and standard picture profiles. 
• 4K DCI/UHD ALL-I/IPB, 59.94p

4K HQ Mode 

• All 4K HQ options no matter the resolution or frame rate. This includes Log, HDR PQ, and standard picture profiles. 

4K 60p Crop Mode 

• Only 4K DCI/UHD ALL-I/IPB, 59.94p. Frame rates of 29.97/24/23.98p are not limited by heat. 

High Frame Rate Mode 

• 4K DCI/UHD ALL-I, 119.9p 

A simple way to think of it is anything above 4K 30p, even in crop mode. Essentially, 8K, 4K HQ modes, 4K 60p, and 4K 120p will be limited in record time.  All other modes top out at 29 minutes and 59 seconds. e.g. Normal mode 4K DCI at 29.97/24/23.98p or 4K UHD 29.97/23.98p. Or crop modes not shooting 59.94p. Record modes not limited by heat can start recording immediately. 

The Tests

Your results may vary depending on your conditions as well as the type of memory cards used. Not all memory cards are built the same. Some dissipate heat better than others. The same for climate conditions.

For this test, a SanDisk Extreme Pro CFexpress Type B card was used. It has a capacity of 512 GB, a read speed of 1700 MB/s, and a write speed of 1400 MB/s. 

Each test was started from a cold start. Meaning, it was not turned on or used, or left in the sun before the test. Each main test started with its potential "maximum record time" allowed before rolling. The camera's Overheat control feature was turned on. 

Test 1 - 8K RAW Outdoor 

The camera started at a cold start. It was not turned on prior to the test for at least 12 hours, nor was it sitting in the sun at all before the test started. The R5 was placed on a tripod in direct sunlight. The location was Los Angeles at 2PM PT. The temperature was 81° F. The camera recorded continuously without stopping. 

Camera settings: 

• 8K RAW, 29.97p
• Turned off: IBIS, Lens IS, HDR PQ, Log 

Maximum record time displayed: 15 minutes 

Results: 

• R5 overheat icon start flashing: 16 minutes 23 seconds 
• R5 stopped recording and shut down: 19 minutes 29 seconds

Recovery: 
The camera was removed from the direct sun and put into the shade outside. The power was kept on and the display setting was turned to 30 minutes in order to view when the overheat icon would stop flashing. The CFexpress card was kept inside the camera. No fans or ice of any sort was used to help cool the camera. This is the same for all the tests. Keep in mind, by turning off the camera, or even removing the card, it may reduce the recovery time. 

Overheating recovery time: 17 minutes 13 seconds

The available record time turns red after the R5 overheats and shutdown

Continued Testing: 
With the overheating icon flashing, the R5 could not record any of the formats that are limited in record time. 8K, 4K HQ modes, 4K 60p, and 4K 120p were unavailable. You can select them, but the R5 won't record them. On the LCD the record time will display 00:00 in red. 

As the R5 cools down, the resolutions that are limited will start to display available record times. 1 minute, 3 minutes, 5 minutes, etc. The first one to become available was 4K at 59.94p. After the overheat icon stopped flashing in this test, the 8K RAW format was given 3 additional minutes of record time after. The camera was immediately put back into the direct sunlight and into record mode.  

The second recording lasted 4 minutes 16 seconds before the camera powered off and shut down. 

After it shut down, we flipped the power switch off and then back on. The camera was able to power right back up. It was placed in the shade and the power was left on. The CFExpress card was left in the slot. The recovery time for the second recording took 52 minutes. After the overheat icon stopped flashing, the R5 showed 3 minutes of recording on the display.  

The third recording lasted 3 minutes and 11 seconds before the camera powered off and shut down. 

After it shut down the third time, the power button was immediately turned off and back on. 

Even after all three 8K RAW tests, the modes not limited by heat were available to record immediately, including 4K DCI 29.97/23.98p. After the third 8K RAW test, the camera was flipped to 4K DCI at 23.98p and placed in direct sun. The outside temperature dropped to 76° F. Pressing record, the record time maxed out to 29 minutes and 59 seconds. The record button was pressed immediately for a second recording, and it too lasted 29 minutes and 59 seconds without issue. A third 4K DCI at 23.98p recording was made, and after 10-minutes, we got kind of hungry and went back inside. 

Test 2 - 8K 10-bit 4:2:2 Log Outdoor

As with the first test, the camera started out cold. It had a full 15+ hours to recover. Prior to the test, the R5 was not turned on or left in the sun. The location was Los Angeles at 9AM PT. The temperature was 68° F.

To start this test, over 1,500 photos were taken first in continuous order using the three different shutter modes. Mechanical, electronic, and electronic 1st-curtain. Each shutter mode was paired with a different drive mode. High speed continuous +, high speed continuous, and low speed continuous. The image quality of the photos were 3:2 RAW+ L (8192 x 5464). HDR PQ was turned off. At least 500 photos in each paired mode was taken. 

Using the same San Disk CFexpress card, the camera was switched into movie mode using the settings below: 

Camera settings: 

• 8K DCI ALL-I, 29.97p
• Turned on: IBIS, Lens IS
• Turned on: Canon Log, Color Matrix EOS Original
• Turned on: View Assist
• Turned off: HDR PQ

The camera recorded continuously. It was operated fully handheld and steadily walked around a designated path that was partially in the shade and in direct sunlight. The camera was constantly moving to make the IBIS and lens IS work as much as possible. The focal length was continually zoomed from 24mm to 105mm, and the focus point was changed during the test. The idea was to push the camera well beyond what would be considered normal use in terms of operating. 

Maximum record time displayed: 15 minutes 

Results: 

• R5 overheat icon start flashing: 14 minutes 39 seconds 
• R5 stopped recording and shut down: 17 minutes 41 seconds

Recovery: 
The camera was removed from the direct sun and put into the shade. The power was kept on and the display setting was turned to 30 minutes in order to view when the overheat icon would stop flashing. 

Overheating recovery time: 9 minutes 37 seconds

Continued Testing: 
After the overheating icon stopped flashing, the R5 displayed 1 minute of 8K recording. It was immediately put back into record mode and the same process started again. 

The second recording lasted 1 minute 18 seconds before the camera powered off and shut down. 

After it shut down, we flipped the power switch off and then back on. The camera was able to power right back up. It was placed in the shade and the power was left on. The recovery time for the second recording took 46 minutes. The R5 showed 3 minutes of recording. 

The third recording lasted 2 minutes 10 seconds before the camera powered off and shut down. 

Similar to the 8K RAW test, all record modes that are limited by overheating were not available as a record option. The ones not limited could be used immediately. A test of 4K DCI 29.97p was run for 29 minutes and 59 seconds. It maxed out successfully without interruption. 

Test 3 - 8K RAW Indoor 

Again, the camera had 12+ hours to recover. The indoor test was not in direct sunlight. The temperature of the room was 67° F. The camera was set on a tripod. 

Camera settings: 

• 8K RAW, 29.97p
• Turned off: IBIS, Lens IS, HDR PQ, Log 

Maximum record time displayed: 15 minutes 

Results: 

• R5 overheat icon start flashing: 16 minutes 53 seconds 
• R5 stopped recording and shut down: 19 minutes 39 seconds

Overheating recovery time: 19 minutes 58 seconds

Continued Testing:
After recovery, the R5 displayed 3 minutes of record time. As with previous tests, it was put back into record mode immediately. 

The second record time lasted 3 minutes 10 seconds before shutting down and powering off. 

It took the R5 approximately 56 minutes to recover from the second recording. It displayed 5 minutes of record time. Again, it was put back immediately into recording for the third recording. 

The overheating icon came on at 2 minutes and 47 seconds. The third recording stopped at 4 minutes 23 seconds before powering off and shutting down. 

Test 4 - 4K 60p Indoor 

This test was done indoors and not in direct sunlight. The temperature was 63° F. This is the normal mode, uncropped version of 4K 60p. The camera was placed on a tripod and recorded continuously using the camera settings below. 

Camera settings: 

• 4K DCI ALL-I, 59.94p
• Turned on: IBIS, Lens IS
• Turned on: Canon Log, Color Matrix EOS Original
• Turned on: View Assist
• Turned off: HDR PQ

Maximum record time displayed: 29 minutes 59 seconds 

Results: 

• R5 overheat icon did not flash but the recording stopped automatically: 29 minutes 59 seconds

Overheating recovery time: approx. 12 minutes

Continued Testing:
After recovery, the R5 displayed 5 minutes of record time. It was put back into record mode immediately. 

The overheating icon started flashing at the 3 minute 41 second mark. The R5 shut off automatically after 6 minutes 04 seconds. Instead of letting it recover a third time, the camera was left off. 

Test 5 - 4K 120p Indoor 

This test was done indoors and not in direct sunlight. The temperature was 68° F. The camera was operated handheld and was moved in a circle. The lens was constantly zoomed from 24mm to 105mm and the focus point was changed periodically. The idea was to push the IBIS and lens IS outside of what's considered normal use.  

Camera settings: 

• 4K DCI ALL-I, 119.9p
• Turned on: IBIS, Lens IS
• Turned on: Canon Log, Color Matrix EOS Original
• Turned on: View Assist
• Turned off: HDR PQ

Maximum record time displayed: 7 minutes 29 seconds 

Results: 

• R5 overheat icon did not flash but the recording stopped automatically: 7 minutes 29 seconds 

Continued Testing:
After the camera automatically stopped recording, the R5 displayed 5 minutes of record time. As with previous tests, it was put back into record mode immediately. 

The second record time lasted the 6 minutes 07 seconds before shutting down and powering off. 

Recovery:
It took the R5 approximately 11 minutes to add an additional 2 minutes of 4K 120p. A third attempt was not made. 

Test 6 - 4K HQ Mode Indoor 

The test was done indoors and not in direct sunlight. The temperature was 74° F. The camera was placed on a tripod and recorded continuously.  

Camera settings: 

• 4K DCI Fine ALL-I, 29.97p
• Turned on: IBIS, Lens IS
• Turned on: Canon Log, Color Matrix EOS Original
• Turned on: View Assist
• Turned off: HDR PQ

Maximum record time displayed: 25 minutes 

Results: 

• R5 overheat icon start flashing: 23 minutes 17 seconds 
• R5 stopped recording and shut down: 27 minutes 09 seconds

Overheating recovery time: approx. 13 minutes

Continued Testing:
After recovery, the R5 displayed 5 minutes of record time. As with previous tests, it was put back into record mode immediately. 

The second record time lasted 6 minutes 19 seconds before shutting down and powering off. 

Test 7 - 4K 60p Crop Mode Indoor 

This test was done indoors and not in direct sunlight. The temperature was 76° F. The camera was operated handheld and walked in a circular path. The focal length of the lens was constantly changed, and the focus point was adjusted every so often. 

Camera settings: 

• 4K DCI ALL-I, 59.94p
• Turned on: IBIS, Lens IS
• Turned on: Canon Log, Color Matrix EOS Original
• Turned on: View Assist
• Turned off: HDR PQ

Maximum record time displayed: 20 minutes 

Results: 

• R5 overheat icon start flashing: 18 minutes 53 seconds 
• R5 stopped recording and shut down: 21 minutes 11 seconds

Overheating recovery time: approx. 15 minutes

Continued Testing:
After recovery, the R5 displayed 3 minutes of record time. As with previous tests, it was put back into record mode immediately. 

The second record time lasted 3 minutes 10 seconds before shutting down and powering off. 

Other Possible Tests

There are dozens of scenarios that could have been tested. For example, shooting 2,000 photos followed by 5 minutes of 8K RAW, then 10 minutes of 4K DCI 59.94p. Then shooting more photos before going back to 8K DCI. Or another scenario where you're shooting less in direct sunlight at 4K UHD 59.94p and then jumping into 8K DCI Log, then shooting RAW photos, then flipping back to 4K DCI 29.97p, then back to 8K DCI. Or shooting only for 5 minutes at a time, then waiting 5 minutes to record again. Or stopping the recording as soon as the overheating icon first appears. Endless combinations. 

For this test, the control was continuous recording until the camera overheated and shut down. We wanted to push the R5 to see how it performed recoding non-stop. 

Final Thoughts

What does this all mean? The obvious is that R5 is most likely going to overheat – no matter if a single record mode is selected or a combination of multiple ones. The bigger caveat when it does overheat is that those limited modes are essentially ineffective until the camera completely cools down. Sometimes it can take up to 12 hours for the "maximum recording time" to return. Meaning, if out of the gate, you get 20 minutes of 8K record time, when the camera overheats and shuts down only once, it may take a long time for it to fully recover back to that original 20 minutes. 

Yes, you may get between 1 and 10 minutes of record time for a second or third recording, but based on our tests, the R5 takes an extended period of time to get back to square one. This is especially true when the R5 shuts down due to overheating a third time. Again, you may see different results based on the area you're shooting and the type of memory card. 

It's also critical to note that all these tests started from a cold start. Simply turning the camera on and using it will reduce the "maximum recording time" for each mode limited by heat. What does that mean? Let's say you simply turn on the camera and adjust the menu settings for an extended period of time. Or run 4K DCI 30p for 10 minutes. Or keep Live View mode on and walk away from the camera. The camera will heat up, and thus, it will reduced the "maximum recording time" for those formats.

So even though you may not have recorded 1 minute of 4K 120p, you may not get the full 7 minutes and 29 seconds after an extended amount of use. It may be reduced to 5 minutes before you even hit record. The reduction of time happens fairly quickly once the camera is powered on. Between 5-10 minutes of general use, the "maximum recording time" can see a reduction in some resolutions like in 4K HQ modes. 

In other tests, recording in ALL-I or IPB did not extend the time by any significant margin. The same is said for disabling/enabling Canon Log or HDR PQ. What we did find was by lowering the power savings times in the camera – Display, Autopower, and Viewfinder – the camera will turn itself off faster reducing the internal heat.

So, if your main workflow requires 4K DCI or 4K UHD 29.97/23.99fps 10-bit 4:2:2 with a Log gamma curve option, the R5 has you covered. Albeit there is a 29 minute 59-second record limit, but that can be immediately started again after being maxed out without overheating. If you're already in the Canon ecosystem, then the R5 may be worth the consideration. For now, the R5 should be looked at as a 4K mirrorless hybrid that has options for 8K, 4K 60p, 4K 120p, and oversampling, rather than an 8K workhorse video camera. The physics of the camera limit the latter. 

There are other plenty of other options out there if you do need 8K, longer 4K 60p record times, or longer 4K 120p Hopefully, this test will help you arrive on a decision.