The Canon EOS R6 Mark III: almost perfect
9.12.2025
The Canon R6 Mark III proved to be virtually flawless in our test. The video feature’s been significantly improved compared to its predecessor, and its fast sensor also makes it suitable for wildlife and action photography.
Camera reviews are getting increasingly boring. This is especially true for devices costing 2,000 Swiss francs or euros and more. In this price range, you now have a wide selection of excellent cameras that can do practically everything well. However, this doesn’t stop the fanboys of various brands calling other brands’ models scandalous outrages and absolute disasters. You don’t have to take them seriously.
The Canon EOS R6 Mark III is another camera in this price segment, released almost simultaneously with the very similar Sony Alpha 7 V. The Nikon Z6 III – which is no longer brand new – is considered another direct competitor. The table below gives an overview of the three models and Canon’s predecessor, the R6 Mark II.
Excellent ergonomics with better slots
The R6 Mark III looks and feels virtually identical to the previous model. The manufacturer hasn’t changed the button layout. And they didn’t need to, as the feel and ergonomics are excellent. It seems Canon’s finally settled on the final body design. The first mirrorless models saw a lot of changes and wild experiments – does anyone remember the EOS R’s touch bar?
If I was being really picky, I’d point out that Canon hasn’t improved the viewfinder and LCD. The Nikon Z6 III has slightly better resolutions, as does the Canon EOS R5 – which is over five years old, making it cheaper. Comparing them directly, I found that both the viewfinder and the screen on the R6 Mark III are brighter.
Under the bonnet, Canon’s improved two things. First, the R6 Mark III has a full-size HDMI port. In his review of the R6 Mark II, my colleague Samuel complained about the fiddly micro-HDMI port. There’s also an improvement to the card slots: instead of two SD slots, there’s now one CFexpress Type B slot and one SD slot. CFexpress is faster than SD, and that’s relevant for this camera. It can produce videos and continuous shooting at such high data rates that SD cards can’t keep up.
Image quality: higher resolution = better
The first thing that stands out in the specifications is the increase in resolution from 24 to 32.5 megapixels. A clear improvement. While this makes the individual pixels slightly more susceptible to image noise, interpolation of the same detail solves this issue almost entirely. And the image is sharper.
The biggest advantage of higher resolution is that you can crop the image more tightly. This is important with small birds, for example, where the focal length’s often too short, and, even if it’s not, the nimble little critters rarely fill the frame. Here’s an example taken with the Canon EOS R6 III, where the goldfinch still appears sharp despite significant cropping.
Dynamic range and image noise are what we’ve come to expect from full-frame cameras for years now. There haven’t been any significant developments in this area for quite some time. High-level development has stagnated.
No ifs or buts, just fast
The Canon EOS R6 Mark III can shoot 40 frames per second with its electronic shutter (12 with the mechanical shutter). Its predecessor could do this too, but its usefulness was limited. Such a high frame rate is only required for extremely fast movements; which is exactly where the rolling shutter effect was a problem with the R6 Mark II. Not so with the R6 Mark III: it’s so minimal that you can use the electronic shutter – and therefore the high frame rate – without a second thought.
In the fan test, the Canon R6 Mark III performs just as well as the Sony A7 V. This is despite the fact that the Sony camera has a partially stacked sensor, while the Canon camera doesn’t. The readout speeds of the Canon camera are exceptionally good for a non-stacked sensor.
Canon’s increased the buffer size compared to the previous model. It’s now enough for 280 RAW photos – that’s a full seven seconds at the fastest continuous shooting rate. If you want to shoot the next burst shortly afterwards, you’ll need the CF card. The photos are saved to the card faster, and the buffer can be cleared for the next shot.
If you press the shutter button a little too late when shooting wildlife or sports scenes, pre-recording means you’ll still get your shot. With the shutter button half-pressed, the camera continuously records to the buffer, but it only saves the image permanently when you press the shutter button. This gives you images taken up to half a second before the actual shutter release. Unfortunately, in my test, this only worked at the highest continuous shooting rate. I’d love to use it at 20 fps as well, with a one-second delay. I don’t understand why this isn’t possible.
What’s more, pre-recording’s become more user-friendly. The images appear normally and are no longer embedded in a video container from which individual files then have to be extracted.
Issue-free autofocus
In a comparison test with the Sony A7 V, face and eye detection worked perfectly on both cameras. As you can see in the video below, there were no noticeable differences. In challenging situations – such as when focusing directly into the light – both cameras occasionally experienced glitches. These manifested themselves somewhat differently with the Canon model than with the Sony. The Sony’s autofocus sometimes failed completely. The Canon only focused on the face rather than the eye, and was sometimes a bit slower. Overall, I consider the two cameras to be equal in terms of autofocus.
Image stabilisation’s A-okay
According to CIPA tests, image stabilisation compensates for up to 8.5 exposure stops. While the camera only achieves this value in combination with the stabiliser of a lens, it’s still a good result. This is because the stabiliser has to improve along with an increase in resolution to achieve the same CIPA rating, as even a minor camera shake becomes visible.
I took some test shots to get a rough idea – with a non-stabilised lens at 50 mm and with a stabilised lens at 200 mm. In both cases, the image is sharp with stabilisation at a half-second exposure time, but not without.
Powerful video feature
Canon’s made the most significant improvements to the video feature compared to its predecessor. The sensor from the Canon EOS R6 Mark III’s also used in the Canon EOS C50. This is a video camera with correspondingly strong video specifications, which now also benefit the R6 Mark III, including 7K video, Open Gate, 4K oversampling up to 60 fps and 120 fps (without oversampling) without cropping. One slight disadvantage compared to top-of-the-line cameras such as the Canon EOS R5 II is that the camera can only record 7K video in RAW format.
The C50 has active cooling to prevent overheating during long video recordings at high frame rates. The R6 Mark III doesn’t. So, I conducted an overheating test using 4K50 Fine – the quality setting that uses oversampling. It took 38 minutes for the camera to shut down due to overheating. This was all done at room temperature, with the screen unfolded and the camera on a table. The runtime would’ve likely been shorter with the screen folded in – and possibly slightly longer if it’d been mounted on a tripod.
Considering the camera isn’t actively cooled, I think this is a good result. It should be good enough for most purposes. According to YouTuber Gerald Undone, the Sony A7V doesn’t overheat at all until the battery’s empty, beating its Canon rival.
Because battery life depends on environmental conditions, you need warnings. A sudden shutdown would be annoying. Canon has dealt with this well. The current camera temperature is displayed on a scale of 1 to 10. At 8 out of 10 bars, it starts flashing red, and the recording light on the front also flashes. After this urgent warning, the camera continued to run for another eight minutes.
Without oversampling, 4K50 or 4K60 recording runs practically indefinitely. In our test, the camera switched off after about two hours – not due to overheating, but because the battery was empty. Even with RAW recording, the bottleneck wasn’t overheating – it was storage space. The 327 GB of free space on the card was only enough for 15 minutes, which is far too short to cause the camera to overheat.
The video feature has virtually no weaknesses. Pre-recording also works with video, thankfully up to five seconds. The minimal rolling shutter effect, the reliable autofocus and the built-in image stabiliser – which the C50 doesn’t have – also benefit moving images. The large HDMI port and the tally light – which indicates recording from the front – round off the positive overall impression.
Canon EOS R5 comparison
The Canon R6 Mark III is currently priced similarly to the R5. While the R5 dates back to 2020, it was Canon’s flagship model at the time and remains an above-average camera. The R5 offers a higher resolution (45 megapixels instead of 33), 8K video and a small secondary screen on the top. However, the Canon R6 Mark III also has its advantages. These include a faster continuous shooting rate and pre-recording, a larger HDMI port and a tally light, as well as easier switching between modes – especially between photo and video. The R5’s quick menu’s also not customisable. This shortcoming was addressed in later Canon cameras, but Canon never released an update for the R5 to enable it.
In a nutshell
A good allrounder, especially for action and video
The improvements to the Canon EOS R6 III have made a well-rounded, coherent camera. In terms of video, the manufacturer hasn’t just introduced better formats, it’s also put together a comprehensive package for demanding users, including tally light, a large HDMI port and low rolling shutter. Similarly, in wildlife and action photography, 40 fps is now truly usable thanks to low rolling shutter, pre-recording and a large buffer. The addition of a CFexpress slot also makes sense here.
You’d need a magnifying glass to find this camera’s weaknesses. The viewfinder could have a higher resolution, and I’d have liked pre-recording to be possible at 20 fps, not just 40.
The R6 III’s a great camera for anyone who wants to shoot videos or photograph sports and wildlife. The higher resolution compared to its predecessor also benefits other areas such as landscape photography. However, the Canon EOS R5’s also an alternative – currently priced about the same as the R6 Mark III, but with (even) higher resolution.
Pro
- Excellent feel and ergonomics
- Fast and reliable autofocus
- Powerful continuous shooting feature
- Low rolling shutter effect
- Powerful video feature
Contra
- Pre-recording only at maximum speed
- The viewfinder and screen could be better
David Lee
Senior Editor
David.Lee@digitecgalaxus.chMy interest in IT and writing landed me in tech journalism early on (2000). I want to know how we can use technology without being used. Outside of the office, I’m a keen musician who makes up for lacking talent with excessive enthusiasm.
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