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The Canon EOS R and Sony a7 III fill an interesting role. Neither camera is the newest or most impressive, but they still offer a suite of professional capabilities at a lower price than their top-of-the-line versos. They are both excellent options for enthusiasts outgrowing lower-tier cameras or for semi-pros who can’t yet justify the cost of the flagships. They also offer a great starting point for someone getting into (or converting to) either the Sony or Canon ecosystems.

With both cameras being about 3 years old and coming down in price, it’s a good time to look at how they compare and see if one would be a good choice for you.

Canon EOS R vs. Sony a7 III Specs

Introduced in 2018, Canon’s EOS R and Sony’s a7 III have largely shared the same space and targeted the same buyers, though the two cameras followed fairly different paths to come into being. 

The EOS R, Canon’s first foray into the full frame DSLR-style mirrorless format, was largely seen as just the 5D Mark IV stuffed into a mirrorless body. With the 5D Mark IV being a powerful DSLR that was strongly aligned with the needs of professional shooters, the EOS R came packed with a strong set of professional-grade features, even though they were no longer strictly “cutting edge.”

The Sony a7 III, on the other hand, was the most recent addition to Sony’s already impressive and well-known mirrorless lineup. Sony’s approach for their full frame Alphas has been to continuously fill out their feature sets with the most exciting, cutting-edge options available. The a7 III specifically was designed to be their “budget” offering (now that role belongs to the Sony a7C), benefitting from a host of features trickling down from more powerful models, offering huge capabilities for the price (but not necessarily specializing in any one feature). In other words, it offered the best it could for the widest variety of shooting situations.

Despite their differences in lineage, both cameras ended up fitting a very similar niche: full frame mirrorless bodies introduced at around (often under) $2,000 that offered all the capabilities that most shooters could ever want, even if they didn’t necessarily include the most advanced specs.

Canon EOS R vs. Sony a7 III Features

Looking at the chart above, there are definitely specs that favor each camera. But let’s dig a little deeper into their features to see if one camera might best fit your needs.

Sensor Resolution

While sensor resolution is certainly not the be-all-end-all factor, it’s a good starting point for a comparison.

Both cameras are in a relative sweet spot, offering enough resolution for all but the most extreme uses while not packing in so many pixels that storage and processing demands start to take a major hit. Canon’s 30.3 megapixel sensor will give you more cropping capability than Sony’s 24.2 megapixel, but for most shooters either will be more than enough. An easier way to think of it is the EOS R will produce 6720 x 4480 pixel images, while the Sony a7 III will produce 6000 x 4000 pixel images. Viewed like this, the difference feels less significant. Both produce UHD 4K at 3840 x 2160. 

Autofocus

One of the benefits of comparing cameras a few years after release is that updates sometimes change the comparison. While the EOS R continues to use the much-lauded Dual Pixel AF that has been featured in many of Canon’s DSLRs, Sony’s Eye AF set it apart at launch. In late 2018 or 2019, the a7 III was the clear winner. However, Canon released its own version of Eye AF with the EOS RP, a system that was able to be added to the EOS R via firmware updates. 

Based on real-world reviews, Sony seems to edge out Canon in terms of raw speed for achieving focus, though Canon seems to edge out Sony in overall accuracy. This indicates that actual results are fairly equivalent between the two cameras. 

Of course, how well your autofocus will work does not only depend on your camera body. Different lenses, lighting conditions, distance to subject, and other factors can push one camera ahead of the other. Bottom line, though, is that neither camera is likely to make you wish you had the other in this area.

Low Light Performance

The Canon EOS R has strong low light performance, but if you expect to be frequently shooting in low light conditions, the Sony a7 III definitely outpaces the Canon.

Part of Sony’s advantage comes from the fact that it does have the lower resolution sensor. It’s not a huge benefit, but all else being equal, fewer pixels in the same area will lead to better light sensitivity. Even without this factor, though, the dynamic range and low light sensitivities of Sony’s sensors have been better than Canon’s for a while (though Canon is improving its approach with the R5 and R6.)

If you want to be fully prepared for challenging lighting conditions, the a7 III is probably the better option. 

Image Stabilization

Another area where Sony moves ahead of Canon is in image stabilization. With the Canon EOS R, you are limited to in-lens image stabilization. While some lenses (particularly some of Canon’s new RF lenses) have incredibly impressive IS, Sony’s in-body image stabilization is powerful and offers stabilization no matter what lens you put on the camera. 

For many users, the lack of IBIS in the EOS R will be a deal-breaker.

Video Capabilities

While Canon was the first to offer professional-grade video capability in a DSLR body (way back with the 5D Mark II), mirrorless cameras have significantly pushed the capabilities of their bodies to be hybrid still/video cameras. 

Though both the EOS R and the a7 III can capture impressive footage, if you are wanting powerful video capabilities, the a7 III is definitely the stronger camera.

Perhaps the most discussed advantage of the a7 III is the crop factor when shooting 4K footage. Many hybrid shooters are drawn to full frame mirrorless cameras because of the benefits in field of view and depth of field that a full frame sensor offers. However, the EOS R has a significant 1.74x crop factor, eliminating all of those benefits. The a7 III, on the other hand, can shoot uncropped 4K when shooting at 24 frames per second, or a much smaller 1.2x crop when shooting at 30 frames per second.

Speaking of frame rates, while both cameras max out their 4K recording at 30p, if you’re willing to go down to Full HD, the a7 III will shoot up to 120p compared to the EOS R’s 60p. With the EOS R you have to go all the way down to just HD to get similar slow motion benefits.

Another major strength of the Sony is its aforementioned IBIS system, which is invaluable when shooting smooth, stabilized footage. There are some workarounds with the EOS R, but the a7 III is going to be a much more enjoyable experience when you’re shooting handheld video.

Finally, the Sony offers more features targeting videographers, such as zebras and focus peaking, which are missing entirely on the EOS R.

Battery Life

Another area where the Sony a7 III edges out the Canon EOS R is in battery life. While your exact battery life will depend on what and how you’re shooting, Canon claims a battery life of around 370 shots while Sony claims just over 600. If you routinely shoot a high number of images at a time, the fewer times you have to change your battery, the better.

Ergonomics

Ergonomics is hard to compare because every person will have their own preference, often based on what they are used to. However, if we had to call an advantage to one camera over the other, the advantage would likely go to the Canon EOS R – with caveats that, sorry to say, will probably not make it any easier for you to come to a decision.

While the a7 III is slightly smaller, the weight of the two cameras is almost identical. For many people, the slightly larger body, and especially the deeper grip, of the EOS R will likely fit their hand a little better (though, again, this is a personal preference). 

Aside from the physical ergonomics of the two bodies, one area of usability that is widely regarded as being better with Canon cameras compared to Sony is the menu structure and accessing the different settings and software features of the camera. Sony has long been criticized on this front – their menus and settings setups are considered confusing, busy and buried. 

Another ergonomic thing is the D-pad vs joystick control on the back. Sony is advantaged here with a nice, tactile joystick.

Viewscreens

As with other mirrorless cameras, both the EOS R and the a7 III have dual digital screens for viewing when shooting: the rear LCD and the Electronic Viewfinder (EVF). Which one you use when shooting comes down to personal preference, but Canon provides a better experience when using either.

For the EVF, the biggest advantage comes from the higher 3.69 million dot resolution. Despite having slightly more magnification (0.78x vs. Canon’s 0.76x), Sony’s 2.36 million dot EVF is, frankly, somewhat underwhelming.

For the back LCD, Canon’s is not only slightly larger (3.15” vs. 3”), it also has a significantly higher resolution (2.1M dots vs. 922K dots). Additionally, the EOS R brings Canon’s fully articulating design that makes it a breeze to view from virtually any angle, a feature that is far more enjoyable than the tilting design of the Sony’s rear LCD.

Burst Shooting

Sports and wildlife photographers largely live by their camera’s burst shooting mode, and the a7 III wins here. While its 10 FPS bursts don’t look much different than Canon’s 8 FPS bursts on paper, in the real world that’s 25% more images captured, which can end up being make-or-break in extremely fast shooting environments.

Memory Cards

Both cameras use UHS-II SD cards, but the EOS R is limited to one card slot while the a7 III offers two. While having a second slot isn’t absolutely necessary, it is a nice perk – verging on a necessity – for many shooters. I certainly wouldn’t feel comfortable shooting on only one card, so the Sony wins out in this regard.

A second memory card slot gives you a couple of different options depending on your shooting workflow. If you are shooting a very high volume of images or a lot of long videos, the second memory card can be an invaluable overflow option, allowing you to seamlessly start recording your files onto the second card without having to switch and potentially miss shots during that time. Alternatively, if you are shooting footage that is vital and irreplaceable, the second card slot can be used as an instant backup, recording the images to both cards and ensuring that a memory card failure won’t result in losing important work.

Lens Mount and Ecosystem

At the end of the day, perhaps the biggest consideration when choosing between the EOS R and the a7 III is which ecosystem you want to be part of. Lenses will long outlast any camera body you use, and few people can justify frequently rebuying equivalent lenses in different mounts because they want a different camera body.

Fortunately, both cameras have a robust ecosystem and lens selection, meaning that neither will hold you back.

At launch, the EOS R’s RF mount only had a few options available. Their selection has expanded considerably over the last three years, but there are still fewer RF lenses currently available than Sony’s E mount lenses, especially once you start looking at third party manufacturers.

However, Canon took the step of offering three fantastic EF to RF mount adapters that allow you to use EF or EF-S lenses with no loss of performance (some reports even say that some EF lenses work better adapted to the RF mount than they did natively on older cameras). These adapters also offer some intriguing features, such as the extra control ring that’s on some RF lenses or a rear drop-in filter. With access to EF and EF-S lenses, you get an enormous range of lens selections.

Of course, Sony’s E mount lineup is fantastic as well, particularly its G Master series. If you’re moving up to either the EOS R or the a7 III, your existing equipment can be an incredibly compelling reason to stay within your existing ecosystem, potentially even outweighing any of the considerations above. If you’ve already invested in some Canon gear, the switch to the EOS R will be much easier, financially speaking, than to the Sony a7 III, even when considering Canon’s new mount type.

Conclusion

The Canon EOS R and the Sony a7 III are both incredibly powerful, offering a suite of professional features at a competitive price point. If you’re looking at moving into either the Canon or Sony ecosystems or looking at upgrading from a more entry-level body to something that could be used professionally, they are both fantastic options.

Each camera has its unique strengths and advantages over the other. For many people, the a7 III will likely edge out the EOS R thanks to features like IBIS, a more robust set of video features, better low light performance, better battery life, and faster overall frames-per-second shooting speed. For others, the ergonomics, better screens, and higher megapixel count on the Canon EOS R might be the deciding factors. Plus, the EOS R series glass is exciting and (relatively) new. For me, the dual SD card slots, battery life, and ISO performance of the a7 III win out.

Either way, you’ll get a camera that will allow you to accomplish what you want. Both are high enough resolution for portraits and landscapes, fast enough for sports, and record in 4K. If you’re still undecided between the two, why not try them out and see which is a better fit? No overview/review in the world can compare to actually having hands-on experience with the product.

Tags: Canon EOS R, Mirrorless Cameras, Sony a7 III Last modified: August 11, 2021