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

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


Sensor Type


Nikon Z6: BSI CMOS



Number of AF Points

Canon EOS R: 5655

Nikon Z6: 273

Sony a7 III: 693


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


1080p Maximum Frame Rate

Canon EOS R: 60 FPS

Nikon Z6: 120 FPS

Sony a7 III: 120 FPS


Video Crop Factor

Canon EOS R: 1.74x

Nikon Z6: 1.0x

Sony a7 III: 1.0x


Battery Life

Canon EOS R: 330 Shots

Nikon Z6: 330 Shots

Sony a7 III: 610-710 Shots



Canon EOS R: 1 x SD (UHS-II)

Nikon Z6: 1 x XQD

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



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


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


  • 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


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


  • 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


  • 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


  • 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.


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.

Robert K Baggs's picture

Robert K Baggs is a professional portrait and commercial photographer, educator, and consultant from England. Robert has a First-Class degree in Philosophy and a Master's by Research. In 2015 Robert's work on plagiarism in photography was published as part of several universities' photography degree syllabuses.

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Now i’m moving to sony.

Wow did not know about the battery life of these camera’s.. That’s a new battery an hour at some shoots for me (Sony 2h). No thanks, I’ll wait a couple years.

On my 7RIII battery is enough to shoot ±4 hours of an event.

To see how accurate the CIPA rating of these cameras is for your uses, look up the CIPA rating for what you're currently shooting and compare that to how many shots you actually get. If you're taking 350 shots per hour, my guess is that the CIPA ratings here won't apply to you and you could probably multiply them by at least 3-4.

I don't think it works like that Jonathan. I just think a camera like that needs at least 1000 one battery. No matter what (except in low temps).

Then try it out.
I typically got about 1000 shots out of my 5Ds and 5D Mark IV. I typically get 900-1100 shots out of my A9, depending on how frequently I shoot video and for how long.

Just for reference, I have gotten over 1100 images on my older and outdated a7II. The III is way, way better.

Mirrorless cameras always have worse battery life than comparable DSLR's. But honestly, Camera batteries are so small that I don't see it as much an issue anymore, especially since Nikon and Canon made their cameras backwards compatible for their batteries.

None of the above.
I know that they're not full frame, just a lowly crop sensor, but Fujifilm can take my money for the X-T3.

There's no point in going into the details but each of these cameras were made a certain way for reasons you don't explore and are completely ignored with a spec list. You should revisit your comparison after the Canon and Nikon cameras have been in the field for a while. Of course, by then, Sony may have a newer model too. :-)

You mean to not harm their other priducts? That is the only thing crippling the Canon and Nikon offerings. But they didn't have the guts to make them great.

When I read comments like yours, I think to myself, 'What was their point?' If you were trying to be funny, you should probably add a winking smiley face. If you're trying to be insightful, you should probably add more detail. In any case, I don't get it.

They crippled the new mirrorless bodies in an attempt to achieve good market segmentation. It crippled the body for large segments of possible users. Canon didn't want a body to encroach on their better DSLR's, so chose to make poor choices to limit the potential of the new bodies. The low video options with a lack of solid framerates? Artificial. Could have been better.to make it a video powerhouse. Same goes for the silly 1.7x crop. For the love of God, Canon, you were so damn close! A design that doesn't incorporate 2 card slots? It screams that Canon does not want their large stable of pro users (think weddings and events) where redundancy is vital. Canon made this a body for affluent hobbyists. Because thatis who they want to sell to.

eventhough Nikons buffer is smaller it takes just over 1.5 seconds to unload it so you are ready to go again .. Sonys buffer is large but than it unloads for almost 50 seconds ..

But it is very hard to fill A7's buffer, and you will be chocked by the 1.5 seconds on Nikon very often.

sure .. that is true .. just putting some more info to those paper specs .. all deppends on usage .. I usually dont go over 10-15 pics in burst, in that case I would be better of with Nikon fast unloading. Another thing is that in Sony case those 89 pics in buffer are compressed and not lossless compression if it matters to somebody .. if you wanna lossless files than you are sitting at ~35 buffer size (which is not that far from Nikons lossless ... not sure what files Canon does with 87 buffer but given that if you want AF you are down to 5 FPS and it almost doesnt matter as it is too slow for what I would need big buffer)

Ah yes! Thanks for mention that the Sony files are compressed. I forgot to mention it in my post. And when using no compression Sony can only 5 or 6 pics per second (I doesn't have the correct number in mind).

You know what they say about version 1.0? Let these offerings hit the field and stay there a minute or two. Personally, mirrorless or not is meaningless unless they outperform what I currently have. If they do, then please, take my money. :)

I suspect that will be most people's approach. Let the early adopters be the guinea pigs as always...

Same here but they are better/more convenient for specific work .. BTS when rolling with sound for example .. better than having D850 on silent box .. or video on Ronin S which is heavy enough without camera. But yep, if doesn't do stills better than what I have, no point spending 3000 on something less comfy to hold

Seems you never had a D850 in your hand. Look at the specs at least ;-)

D810 and D850 are my go to cameras ;) well and good old D700 if needed

...What about the battery grip and the lens releases?

Looks like a pretty fair comparison of the specs to me, including your conclusion. Bravo!

I believe there's another camera called Z7 released as well but is missing from the list.

By the way, whoever shoots long events would be crazy to ditch ANY DSLR and go for a mirrorless.
Even the very worst DSLR can do 800++ shots.

I ditched DSLR for events. A7RIII runs for 4 hours on 1 battery. So, with the grip I’m OK for one day.

Genuinely curious to know whether extreme temperature (hot or cold) has an effect on EVF functionality. That's one of the concerns that I have about mirrorless in general given the fact that you're basically looking into an electronic screen for a viewfinder.

I went to Utah in January, Mexico in May, Nevada in July, and live in San Fran... never have I ever seen my EVF hiccup.

I still do not know where the claims come from of this happening. I’ve owned an a6000, A7ii, and now use an A7Riii daily.

You are looking at a screen the whole time, there is no mirror or optical viewfinder at all. The biggest advantage is that what you see is what you get. If you jack up a shot, you literally were watching yourself jack it up in real time and still pressed the shutter lol

I had a screen frozen on one of my Nikon DSLR's when I was out on a snowy mountaintop once in very cold weather ( -10C, 85% humidity, strong winds ).
Funny thing is, I had the camera most of the time in my face, looking through the viewfinder, yet somehow, the LCD preview screen got frozen and had a big area of frozen pixels that thankfully went away as the camera got heated once I was back in my chalet :D

This review is done for users who want both, still photography and video. How would your assessment look like if a user is only interested in stills and doesn't care about video?

Keep your DSLR ..

Ok, I just don't get it. Of course, specs here, specs there, pros and cons. Anybody who has shot for years with Canon will be able to use this camera for good (low dynamic range? oh well, how many times to you really need more and can't find a suitable workaround? no real 4k? who needs to see the spots on the brides face?). Move to Sony. Move to Fuji. Move to NikonPentaxPanasonic... Stay with Canon. Each way you move you'll spend a whole lot of money and keep Camera business alive. All that gear just helps you achieve your goal, whatever that is. If your goal is spending money, well, keep switching systems.

There's no free lunch.

I find it laughable that it seems like the entire internet wants a tiny mirrorless camera. I absolutely hate the handling and little ergonomic annoyances that my a7r3 has. For me, i'd gladly give up some specs to have a camera feel and operate like i think the R will feel with that large grip, usability improvements like the control wheel and thumb bar, and comfortable grip. If thats an indication of where Canon is going in designing their mirrorless bodies, I'm very excited.

I'll be excited when both Canon and Nikon are competing in terms of specs along with their traditional ergonomics and weathersealing.

Not only _single card slot_, which is something I did not get in the first place as my oooold Nikon D7000 has 2 SD Card Slots, which is something that I truely appreaciate since I have had corrupt cards on a trip to New Zealand which is truely the oposide side of the my world.
But not only _single card slot_, no they also picked XQD. While almost all other camera maker picked SD Nikon goes XQD. Is that their way of thinking how the are different?
Just my 2 Cent.

Well I consider qxd as a good thing. Nothing good about SD card .. and you have pretty much double the speed with qxd .. you don't need to wait for buffer to unload

My favorite thing about Spec comparisons is that they ignore all of the real reasons why someone would want to buy a camera.

Specs mean nothing these days. Theoretically APS-C should be inferior to FF, but I've seen how something as simple and cheap as an XT20 with the 56mm f1.2 blows my 5D3 with the 85L (AF speed, accuracy, high ISO, banding and noise, weight, price)

The A7III is indeed the best FF mirrorless, but in terms of video it can't compete with FUJI, whose footage looks like coming from an ARRI ALEXA rather than (sony) digibeta. The brand new XT3 is now the best for professional video, regardless of sensor size (ARRsI are APS-C by the way)

The best of anything is subjective. What ever you shoot with will have the same results, make the same amount of money, have the same amount of likes, and preserve your past.

So I just happened to be on set with one of Canon ambassadors when they to my surprise bring him EOS R. Only checked photo mode, my brief impressions: body feels nice. Changing focus point when 'touchpadding' on screen feels sluggish and imprecise. Autofocus with new lenses feels instant going from infinity to 1 meter. Viewfinder is terrible. When moving side to side you can see how it is not refreshing fast enough causing vertical lines. Resolution is not high enough, contrast and colors are far from realistic. Picture just like 5d mkIV.. so good with not best but good compared to other Canons dynamic range. It is not small enough to be really compact but it makes it more comfy to hold. And lenses are so big and heavy that size of body doesn't matter anyway. Given video capabilities I would wait for next gen

Despite your comparisons here, and all the hate and praise, I am thinking of ordering Z6 or EOS-R. Most likely will wait for the Panasonic FF because their cameras are the most decent

So there is just a buffer as negative point on Z6..? Hm you know XQD cards will smash SD cards in speeds and with the file size Z6 shoots you might never actually feel that buffer to fill..? Just apples to apples :) It looks to me Nikon+Canon HQ sit down BTS at round table and decided to stop leak of their users to other S+F+P brands in MILC... They did not killed their DSLR market here yet gave very good option to their followers to stay within brand... Time will show how they managed that. I personally try Z6 without a doubt :) Happy shooting everyone

The AF point thing is pretty misleading...

What a onesided comparisson! Did you know, that Nikon also has a Z7 which is to be released before the Z6? What about ergnomics? Wheatersealing, about that? If you take the CIPA values for battery life, there are already videos show the real battery llife of the Zs (I can't talk for the Canon because I haven't seen any so far..). I just had to read the first lines of your "comparisson" and I knew I was sure about the result. And btw. even as Sony has two memory card slots, only one can be used by fast cards. The other one has to stick compatible with their Memory Stick. I bet the performance will slow down if you use the 2nd slot?

WOW on specs alone you know which camera is best without using them I think HANDS DOWN you should offer your review services to camera manufacturers I bet you could make millions due to your physic ability.

Comparison articles are entertaining. All three cameras are equal in regards to the final outcome. The Canon is for enthusiasts. I sure any enthusiast can use any of these cameras and get the same result.

With all due respect for Mr. Robert I consider that this kind of cold comparisons between specifications of different cameras only contribute to the general confusion.

The important thing about a camera is not its number of focus points, but how it focuses, its burst speed, but how many photos of those can be used, how it feels in the hand, focus in low light or backlight?

Personally I think that Nikon and Canon went wrong and late, but surely in the following versions will improve.

Only time will tell what will happen.