Canon EOS R Weather-Resistance Test Results

A very well-sealed, full-frame mirrorless camera

by Dave Etchells | Posted: 05/19/2019

Imaging Resource's weather-testing approach

This is one of an ongoing series of weather-resistance tests of camera systems. Manufacturer claims about weather resistance are all over the map, in part because there's no established standard that's relevant to how photographers actually use cameras. Our aim is to establish a consistent basis for comparing weather resistance between cameras in a way that makes sense for photographers. If you're interested in the details behind the tests, you can read the loooong article I wrote about the rationale behind our camera weather-testing approach.

Camera tested: The Canon EOS R

The Canon EOS R was announced in early September 2018, as Canon's first full-frame mirrorless model. Based on the sensor and electronics of the EOS 5D Mark IV DSLR, it's a roughly mid-range mirrorless model in the current market. Nonetheless, it's presented as a well-built model, in the solid traditional of Canon's professional camera bodies.

We performed our tests with the Canon RF 50mm F1.2 L USM and RF 24-105mm F4 L IS USM lenses attached. Both lenses have sealing gaskets on their mounts, and presumably have internal weather seals as well. In any case, we felt they could be trusted to not allow any water ingress through their seals..

Visible weather seals on the EOS R

We don't currently disassemble the cameras we test, so we can only comment on the weather seals that are visible when you open the various compartments and peel back the port covers.

Lens flange
This is more a function of the lens in use than of the camera itself, but in the case of the EOS R system, all the lenses have similar sealing, namely a thin gasket made of a rubbery plastic material that surrounds the lens flange and seals against a flat part of the camera flange itself. The gasket flares out slightly, so it will deform as the lens is attached to the body flange, making a secure seal against it.

Canon RF-mount lenses are all weather-sealed, with a thin gasket made of rubbery plastic that presses against the lens mount on the camera.

This shot shows a side view of the lens mount on the Canon 24-105mm f/4L IS USM lens. It's interesting to see the different approaches taken by various manufacturers when it comes to weather-sealing their cameras and lenses. As you can see here Canon's RF-mount lenses have a thin, angled gasket made of a rubbery plastic. It feels like a medium-stiff silicone rubber, although I have no idea of its actual composition.

The EOS R's lens mount has five screws holding it securely to the body, but there's a narrow ring of uninterrupted metal surface and a continuous side profile for the lens seal to bear against. We found we could almost entirely avoid water getting sucked onto the mount flange when we removed the lens, if we were just careful to dry the crevice between the lens barrel and camera body thoroughly.

When the lens is mounted to the camera, the seal is pressed tightly against the camera's flange, appearing to provide a very tight seal. (This does bring up an important issue, though: Normally, scratches on a body flange aren't of any particular concern, as long as they don't interfere with the lens attaching properly. They do become a concern, though, if they cross the area where the lens seal presses against the flange. A large-enough scratch could break the seal between lens and body, and allow water in. (Practically speaking, though, it would have to be pretty deep with a softer rubber gasket of the sort on Canon RF lenses, but some lenses with stiffer seals could be more susceptible to scratches on the mating surface.)

While the RF lens gaskets do seem to seal very well against the body flange, as always, it can be tricky to remove a wet lens without water that's caught in the crevice between the lens barrel and body flange from being drawn in and onto the camera's flange. You can see an example of this in the photo below.

This shot shows the lower-left area of the body flange (as viewed from the front), after removing the 24-105mm lens following a 35-minute weather test. This area had the most water on it, although that's probably just down to how I tilted the lens as I was pulling it off. It's almost certain that the water here was wicked-in from what was caught in the crevice between the lens and camera body; I'm pretty confident that it didn't result from any leakage while the lens was attached. As noted above, being more careful when removing the lens after the second, longer test resulted in almost no moisture on the flange at all.

This is a very common issue with many lens/camera sealing systems. If the lens and camera have recently gotten wet, removing the lens will almost always draw at least some water up and onto the body flange, if not into the interior of the camera itself. This can make it a little dicey swapping lenses if you're out in the weather, even if you can shield the camera while you're making the change.

With some designs (like that of the EOS R), you can minimize the amount of water drawn inside by carefully drying the crevice between the lens and the body with something like a microfiber cloth, and then removing the lens very sloooowly. The reason for doing it slowly is that pulling the lens off unavoidably creates a bit of suction, which can draw any wicked moisture inside. If you remove the lens too quickly, this suction could be enough to pull the water into the camera's shutter box. The amount of water is slight, and I've never really experimented with yanking the lenses off quickly, to see where the water might get to (can it make it all the way down onto the shutter?), but my advice is to be very careful opening a wet camera.

The EOS R's battery door has a rubber gasket around about 70% of its perimeter. The hinge area appears to rely upon close mechanical fits and circuitous paths to keep water out of the interior. (Pardon the big fingerprint on the metal part of the door; I need to do a better job of wiping down the cameras before I weather-test them!)

Battery compartment
The EOS R's battery compartment seems to be reasonably well sealed, although it doesn't have the complete, continous gasket I've seen on some other bodies. The silicone rubber gasket extends around perhaps 70% of the circumference of the compartment, with gaps at the latch and hinge area. (And as always, we don't know anything about the sealing within the sliding latch itself, because we don't currently disassemble the cameras we weather test.)

The rubbery gasket does seem to extend beneath the latch slider, although it's impossible to tell whether it actually presses against the latch or just reduces the size of the gap that water could enter through.

It looks like the hinge area relies on a tight fit between the door and camera body and a convoluted path between them for water to travel to reach the inside. The latch area seems similar, with the latch itself creating a torturous path for water to travel to reach the inside, although it does look like the rubber gasket continues under the latch slider. It's hard to tell without disassembling the door whether the gasket maintains positive pressure against the latch elements, though, or if there's a small gap.

The EOS R's memory card compartment has the generally U-shaped gasket arrangement used on many camera bodies. Two strips of gasket material run down the sides, with another along the front. Ribs on the door itself press against these gaskets, the one in front being contacted and compressed when the door is slid shut.

Memory card compartment
The EOS R's memory card compartment has the generally U-shaped gasket arrangement we've seen on a number of other camera bodies. Two strips of foam gasket material run down the sides, with another along the front. Ribs on the door itself press against these gaskets, the one in front being contacted and compressed when the door is slid shut. The rear of the door presses against another foam strip on the camera body when it's slid into its locked position.

This shows a better view of the front edge of the card compartment. There's a foam gasket along the edge that a rib on the door presses against when it's in a closed position. The "teeth" that hold the card door closed fit into the two rectangular sockets you can see on either side. These areas don't have gasket material protecting them, but the close fit of the plastic parts and the circuitous path they present make it difficult for water to enter the body via this route.

Similar to many other cameras, the rear of the EOS R's card compartment door presses against a foam gasket when the door is slid into its latched position.

The card compartment area doesn't have a perfect, continuous gasket, but like other cameras using this design, the sealing seems up to the task, even for pretty significant amounts of precipitation.

At left above is an overall view showing the port cover layout. At right is a closeup of the remote port with its rubber flap held open.

The EOS R's various I/O ports are protected by stiff, rubbery flaps. Ridges along the edges of the flaps press into grooves in the camera body to provide a little sealing, but the real work is done by the projections that plug into the connectors themselves. With a tight fit between the projections and the connector openings, this looks like a very robust sealing approach.

Do be careful to press the flaps firmly when you're closing them, though, because it takes a little force to ensure that the little nubs are in fact fully inserted into the connector openings.

At left above, the USB and HDMI ports. At right above, a closeup of the rubber flap which covers them both.

At left below are the microphone and headphone ports. At right below is a closeup of the rubber flap which covers them both, once again being held open.

Port covers
The port covers on the EOS R consist of three flaps that fit pretty tightly over the ports. The rubbery flaps have projections on them that fit snugly down into the ports themselves. It seems like a pretty secure and positive sealing system, but we did note that it takes a little force to ensure that the flaps are pressed fully into the ports. If you don't take care to apply a little extra pressure, the projections won't be pressed all the way into the ports, which could cause leaks.

We've sometimes seen problems with hot shoes that have a lot of electrical contacts in them to connect to accessories, as rainwater can be conductive enough to fool the camera into thinking there's an unknown accessory attached. The Canon EOS R had no such problem, though, since it has only the few large contacts on the floor of the shoe mount. Somewhat unusually, Canon doesn't ship hot shoe covers with their cameras these days, but in fairness, they offer little to no protection against rain anyway. (Note that we don't test with a flash attached.)

Hot shoe/other
The EOS R's flash hot shoe is a pretty standard design, with only the relatively large electrical contacts that connect to the bottom of the flash's shoe, and it doesn't seem to have any problem with the slight conductivity of rainwater. Somewhat oddly, Canon's ILCs don't seem to ship with covers for their hot shoes. On the one hand, this seems like an odd place to economize on a part that must cost less than a penny, but on the other hand, I invariably lose my hot shoe covers in fairly short order, so maybe leaving them off their cameras is just a concession to reality. :-)

Water exposure tests performed on the EOS-R

Our baseline weather testing protocol currently involves exposing cameras to simulated rainfall at a rate of 1 cm/hour for 35 minutes, while actuating the camera controls according to a set script. (Our thought being that seals around moving components are more likely to leak when the parts they're sealing are moving relative to each other.) For cameras that successfully pass this test, we give them a double-dose of 70 minutes the following day, to see if they can withstand what most people would consider very heavy exposure.

(For reference, meteorologists refer to rainfall rates greater than 0.75 cm/hour (0.3 in/hour) as "heavy rain". So our current test at 1 cm/hour represents a significant level of rainfall, although it's far from what you'd see in the tropics or a thunderstorm. I suspect that few amateur photographers would be likely to stand out in a rainstorm like this for more than 30 minutes at a time, so it seems like a good test for cameras that claim weather-resistance, and in fact does seem a good level for separating levels of resistance in higher-end camera models. We plan to extend our tests to cover lower-end cameras at lower precipitation rates in a system using custom-designed dripper nozzles, but that's some ways off in the future yet.)

In the case of the EOS R, we exposed it to the 35-minute protocol, and found that it did extremely well. We put it in our drybox overnight, and then gave it an additional 50-minute exposure the next day.

Functional observations

The EOS R did pretty well in the tests, with no problems at the 35-minute level, and ultimately failing about 50 minutes into the 70-minute round the next day. (This isn't at all uncommon. The foam gaskets used in essentially all digital cameras don't actually seal against water, they just slow it down. So if your camera gets wet one day, it's that much more likely to leak the day after. It's quite possible that a dry EOS R could survive 70 minutes in a single run, if it were completely dry at the outset.)

One thing that impressed us was how usable the EOS R remained even when wet. It's almost universal that camera touch screens don't work when your fingers are wet, and that the eye sensors used to switch between LCD and EVF displays are often fooled by water drops. This didn't seem to be the case with the EOS R. Here are our observations from these tests:

  • Touch-screen works when wet(!)
    As mentioned, this seemed like a standout feature of the EOS R. The touch-screens on essentially all other cameras we've tested to date having the feature become either unresponsive or very unreliable when wet. This is likely because the water greatly changes the capacitance of your fingertip, so the electronics have a hard time telling where you're pressing, if they're able to detect a touch at all. The EOS R's touch-screen, though, seemed to have no problem with wet fingers whatsoever. Touch-select for autofocus points worked perfectly throughout the testing, as did using the touch-screen for menu operation.

Most cameras with electronic viewfinders these days have a sensor to detect when you raise the camera to your eye, which is used to automatically switch the display from the rear-panel LCD to the EVF. You can see the EOS R's eye-detection sensor here. (It's the small black rectangle beneath the eyepiece.) Most such sensors are easily confused by drops of water on them, making the camera think you're looking through the EVF when you're not. The EOS R was unusual in this regard, as it seemed to have very little problem with false triggering caused by water on the sensor.

  • Viewfinder eye-detect sensor very rarely false-triggered due to water
    This was also unusual. Many cameras use a small infrared sensor next to the viewfinder eyepiece to automatically switch between the rear LCD and electronic viewfinder when you hold the camera to your eye. A drop of water on the surface can reflect light back into the sensor, fooling it into thinking that you're looking through the eyepiece. Different cameras are more or less sensitive to this, but the EOS R seemed almost entirely immune to it. It only triggered incorrectly once or twice when the camera got wet in the face-down position, and immediately cleared when the camera was held vertically again.

  • Pretty complete when it finally gets too wet
    In noting this, I want to underscore that the EOS R actually did very well in our weather-sealing tests. It passed the standard 35-minute heavy rain test with absolutely no problems, and in fact was more controllable than virtually any other camera we've weather-tested, because its touch-screen remained fully functional, and the eye sensor on the electronic viewfinder was largely unaffected by the precipitation.

    It took 50 minutes of additional drenching the following day before it showed any problems at all, but when it finally did give up the fight, it was pretty obvious, as most of the rear- and top-panel control buttons just stopped working altogether. But note that this was after 85 minutes of being fully exposed to heavy rain with no protection whatsoever, an impressive performance compared to many other cameras we've tested so far.

  • Problems go away quickly when the camera dries out again
    Also to its credit, the problems cleared up pretty quickly, once it had a chance to dry out. We toweled it off, put it in our 80-liter Ruggard dry box overnight, and when we checked in the middle of the following day, it was fully functional again. (Do note that it can take quite a long time for cameras' foam gaskets to fully dry, so it's a good idea to leave your gear in a low-humidity environment for a good week or so after it's gotten wet.)

That's pretty much it, from a functional standpoint. The EOS R held up very well in our "heavy rain" test scenario, passing the 35-minute baseline test with flying colors, and withstanding an additional, extended soaking of 50 minutes the following day. Let's take a look at what we found on opening the various body compartments. (The short version: We found no evidence of water anywhere inside the body after the standard 35-minute test, but unsurprisingly found several signs that water had entered the body after the extended 35 + 50 minute exposure.)

Post-Test Analysis

I've separated the results here into two sections: One for our standard 35-minute test, the other for the results of the second extended soaking the second day. My reason for doing so is that our standard test is actually a pretty rigorous one. It's more rain than most casual users would likely be willing to endure themselves, and it's enough to cause poorly-sealed cameras to fail. The longer soaking a day after the first one is intended as a very rigorous test, and deliberately one that very few cameras would survive.

Standard 35-minute "heavy rain" exposure: 100% success

As noted above, the EOS R performed flawlessly throughout the standard 35-minute test, and we found no trace of water anywhere inside the body that we could access without disassembly. It was a 100% perfect score, because not only did the camera not show any adverse signs, but very unusually, its touch screen interface worked perfectly for choosing autofocus points, operating menus, etc., and the eye sensor on the electronic viewfinder was almost never fooled by drops of water on its surface. (And if water did get on it while hanging face-down, it immediately beaded off when the camera was brought upright again.) You could hardly ask for better behavior.

Given that we found absolutely no water anywhere, I won't bother running through all of the individual sections normally included here.

Extended soaking the second day: Full functionality for 50 minutes of "heavy rain"

As noted above, the EOS R survived for 50 minutes on its second soaking, which is a very good performance, given that its gaskets were likely still pretty wet from the first day's torture test. When viewing the alarming-looking images below, keep in mind that this was after very severe water exposure, and that the camera returned to full functionality after drying overnight.

I'm repeating the shot of the wet lens flange from above, just to have it next to the text in this section. No new information, just the photo to accompany the discussion below. :-)

Lens flange and shutter/sensor box
As noted earlier, we've learned to remove lenses verrry slooowly after a weather test, to minimize water trapped in the crevice between the lens and body getting pulled further onto the flange due to the slight suction that happens as the lens is pulled off. We also try to remove as much of the wicked water as possible before opening, by pressing a paper towel or microfiber cloth tightly into the lens barrel/body gap.

In the case of the EOS R, while it was easy to get water sucked in and onto the mounting flange if we weren't careful, we found that the problem could be almost entirely avoided by a little extra diligence in drying out the crevice between the lens and body with a microfiber cloth. Bottom line, we're confident that the lens/body seal on Canon's R-series models is a very good one, and unlikely to leak under any reasonable rainfall scenario.

We saw no water at all in the EOS R's memory card compartment after the shorter test, and only a very small amount after the 50-minute run the following day. It's possible that what you see here was introduced as we opened the card slot, but even if it made its way there past the seals, it was a pretty small amount given the extensive soaking, and the card itself was totally dry.

Memory card slot
We saw no signs of any water at all in the memory card compartment or on the card itself after the standard 35-minute test run. We did see a few small droplets there after the second, longer run, but it's hard to say whether they were the result of water creeping through the previously-dampened foam gaskets or if they just splashed there as we opened the compartment door. In any case, it was a small amount of water, and there was no sign of any water at all on the card itself, even after the second extended soaking.

Here's a closer look at the mic and headphone jacks and the flap which covers both, taken after the second day's soaking. Note that there are indications of water at the base of the nubs that plug into the connector openings. This suggests that water made its way under the flap itself, but the tight seal between the rubbery plugs and the connector openings prevented any water from making its way inside.

Port flaps and covers
As noted in the photo caption above, the port-protection flaps seem to seal very well with the ports themselves, since the soft rubber protrudes down into the connector slots. We saw a bit of water around the edges of the port area, and a few small drops under the central area under some flaps, but they might have just been flicked there as we pulled the flaps open. The flaps are fairly stiff, so it's likely that a little of the water wicked around the edges will get flicked up you you pry a flap open. On the other hand, though, if you look carefully at the shot of the port flap above, you can see a bit of moisture around the plugs that fit into the connectors. That suggests that water might have made its way to the inner parts of the flap, but given the way the projections on the flaps fit down inside the connectors themselves, we're pretty confident that they're up to the task of protecting against even extreme amounts of rain.

Battery compartment
The battery compartment is where we usually find signs of water, if a camera leaked during a test. The top-right control cluster on most cameras is where the most-used controls are located, including the shutter button, various quick-access buttons for things like exposure compensation, sensitivity or other frequently-used functions, and typically front/top and rear control dials for setting things like aperture or shutter speed, or scrolling through menu entries. There are a lot of interfaces between things that have to move and the camera body, so a lot of seals are needed, and ones that can handle motion between the surfaces they're sealing against. When water gets in through one of those routes, it often ends up in the battery compartment.

It took fully 50 minutes the second day -- or a total of 85 minutes of soaking overall -- for the EOS R to give up the fight. Unsurprisingly, we found a fair bit of water in the battery compartment (seen above), and along one side of the battery itself (seen below). While this looks like a lot, we've actually seen quite a bit more from less well-sealed cameras, even partway through the standard 35-minute test.

With the EOS R, we found no signs of water whatsoever in the battery compartment after the standard 35-minute soaking, but quite a bit of it there after the longer 50-minute session the following day. (As mentioned several times already, it's important to note that a camera's seals will behave very differently once they've gotten wet and water has soaked into them than they do when they're dry. That's why our most severe test is a two-step one, with the camera initially exposed for 35 minutes one day and then left to sit overnight before re-exposing it the second day. Even though it's left in a dry box, it's likely that water that has wicked into the foam gaskets will penetrate further in the intervening time. I can't say it enough; if you get your photo gear wet, be sure to give it a good opportunity to dry out before exposing it again.)

As you can see above, we found a fair bit of water on the battery compartment door when we opened it after the extended second soaking. This is far from the worst we've seen, though, especially after such an extended exposure. Some cameras have more water than this in them, even partway through the standard 35-minute exposure. The water on the compartment door had to get there somehow, so it's no surprise that we found traces along the side of the battery itself as well.

You probably noticed the little "clouds" in the viewfinder eyepiece in the shot showing the eye sensor above; here's a closer look at them. It was condensation on the inside of the eyepiece after the second, 50-minute drenching. As noted in the text below, this is less of a problem itself than it is an indication that water did get into the camera body somewhere.

We've seen several cases now in which water that got into the camera evaporated from warmer parts of the body, and then condensed on cooler ones. This was the case after the second exposure of the Nikon Z7, where we found tiny amounts of condensation on the battery compartment door, even though the camera itself never showed any malfunction. With the EOS R, we saw a little condensation on the inside of the viewfinder eyepiece. This isn't surprising, given that we know a fair bit of water got in during the extended soaking, but we always report on anything we see, so here's that report. :-) (Also note that water that's condensed from internal evaporation like this is pretty much guaranteed to not be a problem, because it will be perfectly-pure distilled water and so not conductive, were it on circuit elements. It will dry with absolutely no residue left behind, so it's only an indication of water incursion elsewhere, not a problem in and of itself.)

Summary: How weather-resistant is the Canon EOS R?

Overall, the EOS R seems quite well-sealed against the weather. It passed our standard 35-minute "heavy rain" test with flying colors, and even maintained full functionality of its touch-screen and the eye-detection sensor for its electronic viewfinder throughout. Beyond that, it stood up to 50 minutes of the same soaking the day after, impressive given that its gaskets would already have been pretty wet from the first day's test. And even after this extreme soaking, it returned to full functioning after just overnight drying.

Bottom line, the Canon EOS R has very good weather-sealing, and we'd have no qualms about using it for short intervals in heavy rain, and for longer periods of time in light rain or drizzle.

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