Taking Apart the Canon EOS R5 Mirrorless Camera

Published September 8, 2020

Let’s get one thing out of the way in the first sentence. If you’re here to understand the mysteries of thermal flow in the Canon R5 I can tell you everything I know without doing a teardown: It’s small, it’s weather-sealed, and photo-body cameras have limited ability to get heat out of the camera.

I am NOT a thermal engineer. I believe that it’s better to know nothing than to know what ain’t so. Today, I will take it apart, comment on what I see, show you some fun pictures.

I always speculate some, but I’ll try to be clear about ‘this is what I know’ and ‘this is what I speculate.’ For example, two years ago, we tore down the first EOS R. I showed that there was a big empty space in the camera, about the size of an IBIS unit. That was what I knew. Then I speculated that Canon would NOT put IBIS in their mirrorless cameras because they were so into lens IS.

I am just giving you an example of how much trust to put in my speculations. Or anyone else’s for that matter.

So Let’s Take Stuff Apart!

The camera looks pretty much like the other Canon cameras with the battery door off. That’s the connector for the WFT-R10 wireless transmitter, which is cool: It functions as a 2-battery grip plus provides ethernet as well as wireless connectivity, connecting up to 10 cameras to a server. This is not something I’m interested in myself; the onboard wireless is all I ever need. It seems a cool, albeit expensive, option for high-powered professional-type people., 2020

The battery door itself gives us our first pleasant surprise. In every camera, the battery door is a weak area for leakage. There’s usually some weather-resistant gaskets around the edge, which the Canon R5 has. In addition, the entire flat surface is soft gasket material in addition to the raised gaskets around the edges and hinge area., 2020

The viewfinder rubber comes off next, Canon attaches theirs with a couple of screws rather than a clamp., 2020

Next, of course, comes The Removal of the Grips., 2020

The key to taking off the grips, for those of you doing your own disassembly at home, is to keep as much of the double-sided tape on the grip as you can, which makes it easier to reapply. The grip material surface feels slightly different than earlier models to the touch, but it’s about the same thickness and flexibility., 2020

The cover to the remote control sensor is basically held on by the grip., 2020

And there’s a metal plate covering the area of the card door hinge., 2020

It seems to provide some reinforcing strength, but mostly a smooth surface for the grip rubber to stick to., 2020

Now we have access to most of the screws and can start body disassembly., 2020

The bottom plate comes off next., 2020

The inside of the bottom plates shows us a new thing! We’re used to seeing a bead of rubber felt between the plastic pieces of the body to seal for the weather. Canon now has a soft rubber gasket along the mating edge of the pieces. This is much larger and provides a greater seal area than what we usually see. It seems to be attached to the body (in the old days, I would have said ‘vulcanized’) rather than being glued on., 2020

The same material is used around the openings where the plate seals around other parts. Here they’ve completed the seal for the battery door hinge from the inside., 2020

The metal tripod plate is sturdy and the actual tripod mount replaceable; both of these are things we consider important., 2020

The I/O side comes off next, and again we see that big rubber lip sealing the entire piece. Also, note that both the HDMI and digital out ports are part of the main PCB, so secure your cables; tugging these ports loose will be an expensive main PCB replacement., 2020

Another close up of the sealing gaskets from the side door. When we took these pieces apart, you feel the suction when they disengage. That’s not something we’ve seen in other cameras. The thing about weather sealing is it only takes one weak place to leak, but this sealing seems to be a step up from anything we’ve seen before., 2020

While there are gaskets around the I/O ports, with any port unless the covers are closed, you lose weather-resistant integrity., 2020

Under the card door, there is a thick foam similar to that on the battery door., 2020

And there’s that big rubber gasket where the door plates fit with the rest of the camera., 2020

OK, enough with weather sealing. You know weather sealing is outside my circle of trust, but I might put this within the rhomboid of reduced suspicion. I write off too many cameras from water damage every year to really trust weather sealing. This is good, but weather sealing isn’t about where it is good; it’s about where it can leak.

The next step is to take out the diopter adjustment screw., 2020

And then the back assembly comes right off., 2020

The back has more dials than the original R, but the LCD wiring appears identical; nothing much to see here. Except for the new, coppery colored flex they’re using on the LCD side, but not the switch side. I don’t know why the new flex material, but it is pretty., 2020

As you can see above, a Canon tech made his ink marks when this part passed inspection. Aaron decided to leave his mark of approval, too., 2020

Now we can look into the camera and see the back of the circuit boards. This is immensely more intense and dense circuitry than we saw in the R. First of all, there’s a green sub-board that appears to be about DC power conversion. You can see some hefty wires entering it from the battery compartment. The larger, square chips are TPH8R903NL voltage converters. Over to the left on the black board, the large white chip is a Canon WiFi chip with what looks like an antenna plugging in just above it., 2020

I am NOT an electronics expert, but I do know DC-DC conversion boards have to generate waste heat. How much depends on load, but I’m told 10%-20% of wattage isn’t unusual.

The viewfinder comes out next., 2020

I’ll indulge in my flex fetish and show you a closeup of ‘the argyle flex’. We actually decorate our office with large printed macros of pretty flexes and circuit boards. Yes, I know I need some counseling., 2020

Anyway, with the viewfinder out, the top assembly comes off. Not much different, other than the number of buttons and dials, from the other R top assemblies. Except they’ve put all the connections between the top and motherboard in a single flex; usually, there are several. There is also, compared to the main part of the camera body, a bit of air up here., 2020

The weather sealing is different around the top assembly compared to the rest of the camera. Where we had those hermetically rubber seals along the bottom and sides, we don’t see them on the top. On the top assembly, there is the traditional ‘top plate sticks out over the body plate’ thing., 2020

With the standard foam sealing strips over some of the body plates. So we have the regular overhang and foam sealing on top that gives rain protection, but the bottom, the part you might set in a puddle, is tightly sealed. It makes sense unless we missed a leaking point on the bottom., 2020


There’s not much sealing material over the lens mount area, though, so if there’s a weak point in weather sealing, I guess this would be it., 2020

TOTAL SPECULATION: Maybe the looser sealing at the top, where heat rises, helps heat get out. The chassis is not a huge heat sink, and it’s wrapped in insulating rubber grip material. It radiates heat, of course, you can feel it, but that’s not an uber-efficient way to get rid of heat.

Now we turn our attention back to the main body. That accessory board comes off easily. It’s a single surface board; the backside is smooth., 2020

And a single view for those who do chip quests., 2020

There’s an aluminum heat sink or electronic shield beneath that board., 2020

Electronic shields tend to be quite thin, but this is a manly piece of aluminum, 0.98mm thick. I speculate it’s more about heat than electronics. Notice I said ‘speculate’., 2020

The aluminum shield connects to copper tracings at the top and bottom (and the bottom tracing connects to the metal base plate), plus it sits above the two thermal pads, so I’m feeling pretty comfortable that this transfers some heat., 2020

Peeling back the heat transfer pad shows the four SKHynix SDRAM chips we’ve already been told are there surrounding the main CPU., 2020

We took off the tripod plate next (note, we had to take off that top heat sink before the tripod plate, so they are indeed connected). Notice the tripod socket is screwed, not soldered, to the plate, so it’s easy to replace., 2020

Now we can get a glimpse of the stabilizer/image sensor arrangement. There’s not much air down in there, particularly if you compare it to the original R., 2020

As long as we’re looking around the edges, I should show you the battery door switch, since people have been having a grand old time stuffing things in there to make the camera think its door is staying shut. This is a small, frail switch soldered directly to the motherboard and only held on by the solder. I have it on very good authority (my own) that it’s easy to dislodge the switch from the circuit board with just a little bit of torque, requiring a complete mainboard replacement, which is very pricey., 2020

Having completed our camera body tour, we took out the main PCB., 2020

There’s another big aluminum heat sink on the underside. This one has a layer of electronic insulating tape over the sensor., 2020

Removing this shows another thermal pad underneath the CPU. So it seems Canon is sending the heat from the SDRAM chips to one sink, and from the CPU to another. To some degree. (Get it? Degree?), 2020

Both card slots are part of the main PCB, but we can remove the ejection mechanism for the CFExpress card, getting a look inside. Here you go; a picture of the inside. You can see why we think CFExpress is a lot sturdier than the long, bendable pins of old CF card slots., 2020

Going back to the camera, we get to see the back of the sensor / IBIS assembly and the huge flexes leaving there, as well as the shutter mechanism between the sensor and the battery compartment., 2020

The sensor assembly is held in by three screws. As you can probably see, Canon has changed to shimming the sensor for flatness (in the R they used spring tension screws). Spring tension screws can theoretically be more accurate (depending on how accurately they measure), but I assume the vibration of an IBIS unit could loosen them over time; every IBIS camera we’ve opened uses shims., 2020

The sensor / IBIS unit comes out as a single piece., 2020, 2020

The shimming for this one was 0.45mm, 0.45mm, and 0.24mm, so a pretty significant tilt compensation was made. And no, that’s not unusual for any camera., 2020

The only thing really left in the chassis is the shutter assembly, which is held in place by screws and posts., 2020, 2020

These we don’t take apart, but then neither does the service center these days. Nobody’s got time to line up all the gearing, plus if you mess with it, you have to have factory software to recalibrate the timing., 2020


With the shutter out, the chassis really has nothing left inside but the lens mount, battery case, and a few connection traces. You know something I’ve found interesting in all the jumping-to-conclusions about heat inside the Canon R5? Not one person has tested the heat conductivity of the chassis. (Spoiler alert: it doesn’t conduct heat well.), 2020

Outside of the chassis sits our sensor and IBIS unit, which I’m quite interested in., 2020

We aren’t going to get majorly aggressive here, but we’ll take off the cover plate., 2020

Which comes off easily along with the outer self-cleaning glass plate., 2020

We can’t get an exact glass measurement without taking the sensor apart, and we have a bad habit of breaking glass when we do that, so it will have to wait for the first Canon R5 to die for a more accurate measurement. We estimated the total (including the front piece) at about 2mm, which is Canon standard., 2020


I also wanted to look at how the sensor is supported in the IBIS unit. We’ve found some fractures in cameras where the sensor is supported by several screws-through-plastic-tabs. There is one screw tab you can see above, but that was mostly for the cover plate.

On all the edges of the Canon unit, the sensor is mounted directly to IBIS plate; no tabs. That doesn’t mean it can’t break, of course, or glue come loose. But this seems sturdier to me., 2020, 2020


On the IBIS itself, we can see the permanent magnets; the electromagnets are shielded here, so not completely obvious., 2020


So What Did We Learn Today?

Not much that was surprising. What with the IBIS unit and a more intense chipset, the camera is pretty thoroughly filled up, there are lots of parts and not much air. There’s a new weather sealing method in the lower 2/3 of the camera that seems to give a really, really tight seal. And there we some pretty new flexes which matters not a tiny bit to anyone but me.

The IBIS unit is very compact but well-engineered. There are no tab connections that might be weak points; the sensor is connected to a flat plate around all its edges. That doesn’t mean there can’t be problems, of course, this is a new build, so we won’t know for a year or so.

There seem to be two separate heat sinks, one under the voltage board, another between the main PCB and the sensor assembly, with thermal pads to direct heat to each. At least one of them connects to the tripod plate, which might provide a secondary sink. This is a lot of heat sink compared to most photo cameras, but not even a fraction of what we see in a video camera. What I can’t tell from this is how that heat then gets out of the camera. It’s sure not air circulation.

Given how tightly sealed things are, I’m curious as to where the heat goes to get out of the camera; some further investigation is required there. A lot of people are talking about how the heat should move around inside the camera, slapping some thermal paste around, and doing things to manipulate the heat cut offs.

I’m a simple person. All I can think of is, ‘how does the heat get out of the camera?’ Sure it goes into the metal sinks, but once they heat up, then where? In a small photo camera, there’s not a lot of ventilation/convection current to get let the heat out. This camera is better sealed than most; I doubt there’s very much ventilation at all.

Somebody should look into that.


Roger Cicala and Aaron Closz

September, the ninth year of 2020



Author: Roger Cicala

I’m Roger and I am the founder of Hailed as one of the optic nerds here, I enjoy shooting collimated light through 30X microscope objectives in my spare time. When I do take real pictures I like using something different: a Medium format, or Pentax K1, or a Sony RX1R.

Posted in Equipment
  • Scott

    It doesn’t disprove anything of the sort. It just means that Canon expanded the limits they built into the camera to give better performance. Hopefully, that doesn’t mean greater risk of damage from heat.

  • DR

    Uh, Sony has had overheat problems in all of the mirrorless cameras in BASIC 4K 30 for years now!

    The A7SIII still has issues in hot sun and will shut down before the R5. But the A7SIII is severely crippled to 12 MP making it useless as a pro photo camera and making it easy to shoot 4K because there is no downsampling involved. There is nothing revolutionary there.

  • DR

    This report, along with the new firmware, disproves the whole “cripple timer” conspiracy. But I’m sure people will hold on to that for as long as they hold on to the Bill Gates/Flat Earth theories.

  • DR

    All this is moot now with firmware 1.1.1 as the camera responds very well to cooling. In fact, some people here in Canada are getting basically unlimited recording in 4k 60 with fall temps (10c or so). Others have also been getting near unlimited record times using usb fans. This disproves the whole “hard timer cripple” nonsense.

  • DR

    Such a nice refreshing objective view on this matter as opposed to the subjective, conspiracy theory laden EOSHD/Youtube garbage out there.

  • Paniolo

    @rogercicala:disqus Any plans on taking apart the “less weather sealed” R6?

  • Jose Colon

    Ok, so now I wonder what would happen I f I take this camera to the South Pole, will it crack bcs of the heat being retained in and the cold out? I don’t know I’m just a Sociologist with a photo hobby.

  • Graham Stretch

    I just read it as there weRE some, just a typo or unwanted spell / grammar check correction! No verb needed! ?
    They were pretty looking flexes, not only of interest to Roger! ?

  • Jam005

    An important finding that required a teardown is that the aluminum plate/shield IS attached to the tripod plate. Therefore testing the effectiveness of attaching a peltier cooler to the tripod plate via a rig cage etc. Optimum location of the peltier device/cooling is worth finding out.

  • Jam005

    The R5s Tripod plate + internal aluminum plate = Heat sink. However there’ no dissipation except through the ports. One being latched and the other being covered with gaskets. Forced air cooling the usb ports leaves no path for dissipation quickly abeit some addicional cooling. External cooling via a rear peltier would give some relief although a port would need to be opened for the heat to excape more rapidly as the the transfer rate via the body at the LCD point is very slow. I have connected the SmallRig cage + peltier cooler attached in place of closed LCD. I shall see during IR testing how fast this dissipates that processor heat. This is similar to what Fuji does. Opening ALL the ports during card and battery change in combination with peltier themoelectric cooling is a faster “Full Recovery” solution. As seen in many smartphone and cellphone cooling options. Memo and Blackshark.

  • Jam005

    Exactly, smartphones went through this already with the cell phones overheating and catching fire and banned from airlines at one time.

  • Jam005

    Tripod plate + aluminum plate = Heat sink. However there’ no dissipation except through the ports. One being latched and the other being covered with gaskets. Forced air cooling the usb ports leaves no path for dissipation quickly abeit some addicional cooling. External cooling via a rear peltier would give some relief although a port would need to be opened for the heat to excape more rapidly as the the transfer rate via the body at the LCD point is very slow. I have connected the SmallRig cage using the tripod mount. I shall see during IR testing how fast this dissipates that processor heat. This is similar to what Fuji does. Opening ALL the ports during card and battery change in combination with peltier themoelectric cooling is a faster “Full Recovery” solution. As seen in many smartphone and cellphone cooling options. Memo and Blackshark.

  • So, have you tried comparing the 8K temperatures to what the camera does when shooting in 4K? Let’s say the 8K is only useful in b-roll situations where you’re shooting small clips, well you still have a 4K camera (thats mirrorless and less expensive than the 1D C was when it released) with 45MP for photos and everything else the camera does. But if it’s overheating in 4K are the temperature readings identical at max recording times?

  • Brandon Dube

    I was wrong, you are right. I overestimated how quickly the peak moves to the right as the body temperature is lowered.

  • asad137

    The peak of a 300 K blackbody is around 10µm, so somewhere around the 5-30 µm range for room temperature stuff is about right.

  • asad137

    If they meant white paint is good for emissivity of an object ~ 200F or lower, no – I would very much disagree.

    You would then very much be wrong. The Spacecraft Thermal Control Handbook (Volume I) has room temp emissivity values of ~0.8-0.9 at for common white spacecraft thermal control paints.

    On page 142 of the STC, there’s an example curve for “white paint” (which I assume is some particular paint’s curve that is used as a “typical” curve) that has absorptance > 0.8 starting from 10µm (and longer), which, coincidentally, is right around the peak of the blackbody curve for a 300 K object (and, of course, there’s more energy emitted below the peak than above it).

    But hey, you don’t have to take my word for it. Ask any of the thermal engineers in 382 or 353 (of which I used to be one) and they’ll tell you the same thing 😉

  • obican

    Good call regarding the direction of heatpipes.

  • Brandon Dube

    “thermal infrared” is not well defined. MWIR gives you strong thermal signatures, but is far away from the peak in the radiation of a relatively cool black body. You would need to have wavelengths in the range, say, 25-100 microns, to be at the peak. We made the Herschel space telescope for those wavelengths, which spurred development of a lot of novel measurement methods for things in that wavelength range. Those tools, and that data, is really not commodity at all.

    So if asad means MWIR, I’d agree that a lot of white paints are pretty black in those wavelengths. If they meant white paint is good for emissivity of an object ~ 200F or lower, no – I would very much disagree.

  • Roger Cicala

    I don’t know what’s safe. But I’m sure not surprised it takes a while to cool off once it’s heated up. The latest blog post somewhat confirms that.

  • So, in your opinion, is between 140F and 150F not too hot for inside a camera without any fans? There seems to be plenty of debate on this but if the camera isn’t letting air in then it sure isn’t letting it out so why are people surprised that it takes it an hour to cool off?

  • Roger Cicala

    We’ve seen 140° but that seems to be where it shuts down.

  • Roger Cicala

    I haven’t torn down the newest Sony cameras, but the A7rIII was very well done.

  • Rashad

    I tell you a real story. in 1990 I bought a Sony VHS VCR (yes VHS!!). it was slick and beautiful and much lower profile than other brands. in few months the device started to loose sync minutes after turning on. being a electronic engineer I opened it to investigate. long story short, the Sony’s design was different: to make the profile lower, Sony used a special motor to drive the video heads drum, a motor with the stator built in the main PCB! no other company ever used this design! it heats up and with time distorted the board and lost sync. I NEVER bought a Sony device since then

  • Matt Saunders

    The CPU / image processing chip, the RAM chips, the CFe card etc. of course contribute to a camera’s heat output. Unfortunately, their actual temperatures are quite difficult to measure from the camera’s outside.

    There is, however, one important component whose temperature can be fairly easily measured from the outside: the image sensor.

    Image sensors can also be non-negligible source of heat. Furthermore, if the image sensor heats up, thermal noise in the pixels increases, degrading image quality.

    An interesting experiment would be to take a picture of the Canon R5’s image sensor through the bayonet mount with your infrared camera.

    The bayonet mount should be covered with Saran wrap to emulate the fact that, in normal camera operation, the mounted lens and the lens bayonet’s weather sealing prevent cooling outside air from circulating in the image sensor’s vicinity. Of course, take test pictures with the IR camera beforehand to ensure the particular type of plastic cling film used is transparent to IR and thus doesn’t affect temperature measurements.

    Once it’s ascertained that a layer of plastic film doesn’t influence the IR camera’s readings, here are some measurements that could be taken:

    1) before powering up the Canon R5 — this establishes a baseline for the temperature increases, and is also a sanity check: the temperature reading from the image sensor should, obviously, be identical to the room’s temperature

    2) 10 minutes after power on, the Canon R5 prevented from sleeping but otherwise left idle (camera CPU is executing code, image sensor is active, feeding signal to the EVF). To keep “idle mode” comparisons between various camera models fair, a human should stare into the EVF for the whole 10 minutes, as some cameras might lower the EVF refresh rate, image sensor scan rate and thus lower their power consumption if they detect no human eyeball behind the EVF.

    Give camera a few hours to fully cool down to room temperature, and then:

    3) power it on, immediately start filming 4K video in best quality for 10 minutes, and take temperature measurement.

    This could show differences in heat output (that is, energy efficiency) between various camera manufacturer’s image sensors, as well as the possible influence of maximising the contact area between the image sensor’s ceramic package and the magnesium IBIS frame, as said frame might have a bit of a heat sink effect.

  • Rashad

    OT is NG but MBT

  • Rashad

    Asad137 is right

  • I got the temperature warning icon while shooting stills only (not video) during at least 4 weddings.
    The only way I found around it is to power the camera bodies off while not actively using them, doing this allowed me to get through a whole wedding day without the dreaded temperature warning icon.

    The reports about the temperature warning icon being driven by a timer seem to make sense based on my experience. I have two EOS R5 bodies and they both give me the temperature warning icon after about 2 hours when only shooting stills. Basically with the camera bodies powered on in stills mode they will heat up enough for the icon to display in about 2 hours.

    I updated the firmware on one of the bodies and during the wedding I just shot last weekend I saw that the body with the original firmware had the temperature warning icon displayed after roughly 2 hours and the other body with the new firmware (which had actually taken more images) didn’t have the icon displayed at all.

    I’ll test it again this weekend as I have another wedding. I plan to make a YouTube video on my Canon experience, going from the 5D Mk4 to the EOS R to the EOS R5 and hope to have that posted by the end of September (my 3-month anniversary with the EOS R5).

  • Not THAT Ross Cameron

    LOL, I had to chuckle at that too.
    Maybe “the 7th era of 2020, in the first year of our isolation”. :~)

  • Richard Chan

    My question is how Sony can pack similar functionalities into a smaller camera body, when the inside of R5 is pretty much filled up?

  • Olandese Volante

    I much appreciate your teardown articles and commentary, for exactly the same reason.
    I see engineering as the Art (yes, capital “A”) of practical application of Science, and the true artist learns whenever, wherever there’s something worthwhile to be learned.

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