Mirrorless Spec Comparison and Discussion: Canon EOS R, Nikon Z6, and Sony a7 III

Mirrorless, mirrorless, mirrorless... it's the most public camera debate for some time and if you're already sick of it, don't click this article. We're going to look at the specs of all three of the big brands' mirrorless cameras and see who comes out on top.Now that there are full spec sheets for all three mirrorless cameras, comprehensive comparisons between the specs of the Canon EOS R, Nikon Z6, and Sony a7 III are popping up so you can clearly and coherently see who's in the lead for your specific wants. Now, I'm not going to post a full list in its incredibly detailed entirety, but rather pick what are arguably the most important features so we can discuss them further.

Specs Overview

Sensor Resolution

Canon EOS R: 30.4 MP

Nikon Z6: 24.5 MP

Sony a7 III: 24.2 MP

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Sensor Type

Canon EOS R: CMOS

Nikon Z6: BSI CMOS

Sony a7 III: BSI CMOS

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Number of AF Points

Canon EOS R: 5655

Nikon Z6: 273

Sony a7 III: 693

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Video Maximum Resolution

Canon EOS R: 4K at 24/25/30 FPS

Nikon Z6: 4K at 24/25/30 FPS

Sony a7 III: 4K at 24/25/30 FPS

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1080p Maximum Frame Rate

Canon EOS R: 60 FPS

Nikon Z6: 120 FPS

Sony a7 III: 120 FPS

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Video Crop Factor

Canon EOS R: 1.74x

Nikon Z6: 1.0x

Sony a7 III: 1.0x

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Battery Life

Canon EOS R: 330 Shots

Nikon Z6: 330 Shots

Sony a7 III: 610-710 Shots

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Storage

Canon EOS R: 1 x SD (UHS-II)

Nikon Z6: 1 x XQD

Sony a7 III: 2 x SD (UHS-II)

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Price

Canon EOS R: $2,299

Nikon Z6: $1,997

Sony a7 III: $1,998

Now, there's admittedly a lot I'm missing out here, so for the most comprehensive list I could find, have a look at Canon Rumor's article. The above is highlighting some of the key talking points, avoiding areas where all three cameras tie (Bluetooth, weather sealing, focus peaking, and so on), or where there are myriad caveats (AF detection range for example). In my recent article, I wrote that I was severely underwhelmed by Canon and Nikon's entries in to the mirrorless market, and I stand by that. That's not to say each of their cameras don't come with perks.

For example, Canon's AF points compared to the other two is staggering, with Nikon embarrassingly far behind even second-place Sony. Nikon also offer some of the fastest continuous shooting speeds with up to 12 FPS, but again, these comparisons have so many caveats with file format and so on, it's difficult to succinctly compare them. So, let's get down to brass tacks. Here are the pros and cons when compared with each other. That is, if you were going to buy a mirrorless but didn't know which to choose of the three, this would be useful.

Pros and Cons

Canon EOS R

Pros

• Best sensor resolution
• Best image size
• Best viewfinder resolution
• Most AF points
• Most movable articulating LCD

Cons

• Most expensive
• Single memory card slot
• 1080p only goes to 60 FPS
• No focus stacking
• Lower estimated shutter durability (150k vs 200k for Nikon and Sony)
• Slowest continuous shooting speed.
• Narrowest native and boosted ISO sensitivity
• No in-body stabilization
• CMOS sensor as opposed to BSI CMOS

Nikon Z6

Pros

• Cheapest (by $1)
• Fastest continuous shooting
• Best viewfinder magnification

Cons

• Heaviest (albeit by 15g)
• Worst maximum buffer capacity (by miles: 18 images at 14-bit-raw vs. EOS R's 47 images and a7 III's 89 images)

Sony a7 III

Pros

• 2 memory card slots
• Best maximum buffer capacity
• Best flash sync speed (1/250)
• Best battery life (around double that of the EOS R and the Z6)
• Lightest weight
• Smallest dimensions

Cons

• Lowest viewfinder resolution
• 4:2:0 8-bit HDMI Output (as opposed to 4:2:2 10-bit of EOS R and the Z6)
• Lowest LCD Resolution

Comparison of the Pros and Cons

Now, there are a number of things that jump out at me straight away. Firstly, Nikon's Z6 doesn't have many pros or cons. This is an interesting point of discussion. There are many areas in which the Z6 and the a7 III are like for like, where the Canon falls behind, so I didn't list them as pros for either camera, but rather cons for the EOS R. The Nikon Z6 spec does a lot right, with some bizarre slips, for example the maximum buffer capacity. Its real selling points are largely the same as Sony's a7 III which isn't necessarily a bad thing.

Secondly, we have just how many cons Canon have. I've come under fire for criticizing Canon before, but as somebody who has shot with Canon for over a decade, I'm comfortable calling them out. There are several stand-out cons for me. The first is the 60FPS limit on 1080p video which is not some innocuous deficit in an outdated video resolution; it puts a complete block on the buttery smooth slow-mo that videographers love so much. If you're looking at mirrorless for video, I'd be surprised if this isn't the nail in the coffin for the EOS R. As if that isn't enough, the EOS R has a video crop factor of 1.74x — no thank you. Secondly, we have the single memory card slot.

This is the most contentious point for both the Nikon Z6 and the Canon EOS R and it's a fair criticism. Most pros will not shoot with single card slot camera bodies anymore for a multitude of reasons, and therefore necessarily have to rule out Canon and Nikon. Both will undoubtedly release models with dual slots in the future (with Nikon all but confirming that), but we're not talking about the future, we're talking about the now.

Conclusion

For me, the Sony a7 III is the hands-down winner, with Nikon is second place, and Canon in third. Canon have excelled in certain areas and deserve praise as such, but they've fallen behind — or rather started behind given they're the last of the three to release a mirrorless — in too many crucial areas. Nikon have done well and kept up with Sony's a7 III with important features like in-body stabilization, sensor type, video settings, focus stacking, and so on. It just drops the ball with the single card slot and maximum buffer capacity.

So, what are your thoughts? Am I being unfair to Canon? Am I being too complimentary of Sony? Fire away in the comments.