Canon EOS R vs Sony A7 III vs Sony A7R III

Now that Canon has officially announced its first mirrorless camera, the Canon EOS R, many photographers will be interested to compare it against the latest generation of Sony full-frame mirrorless cameras, particularly the Sony A7 III and A7R III. At $2299, the Canon EOS R fits between the two Sony cameras in price, although it is positioned closer to the A7 III (at $1998). With the Canon name and the company’s famous Dual Pixel AF technology, it promises to be a major force on the market today.

Let’s take a look at the specifications of all three cameras and compare them in the chart below:

Canon EOS R vs Sony A7 III and A7R III Specifications Comparison

As you can see, there are a number of differences between these two cameras, many of which favor the Sony cameras. Even the less expensive Sony A7 III is ahead of the Canon EOS R in some important areas, such as the inclusion of in-body image stabilization (IBIS) and the lack of a 1.74x crop in 4K video mode. The Sony cameras also have higher frame rates with full-time autofocus (10 FPS versus 5 FPS) and dual SD card slots (although only one slot is UHS-II compatible). Sony’s popular Eye-AF system also works in continuous focus mode, unlike Canon’s that only functions in Single-Shot AF (AF-S) mode. So, on paper, both Sony A7 III and A7R III are the winners in most categories.

However, note that the Canon RF mount diameter is much larger than the Sony’s, at 54mm versus 46.1mm. The larger diameter, coupled with a 20mm flange distance allows Canon to have a large angle of incidence of 36.87°, which is more flexible than Sony E mount’s angle of incidence of 31.6°. This is far from a minor advantage (especially in the long run), as it gives Canon more flexibility in designing particular types of lenses, such as their new RF 50mm f/1.2L USM and RF 28-70mm f/2L USM that were announced alongside the EOS R. So, looking to the future, the RF mount has more flexibility over the Sony E mount, akin to the benefits of the new Nikon Z mount.

The Canon EOS R also fights back with its Dual Pixel AF, famously good for video work, as well as its full front / back vari-angle tilting screen – ideal for vlogging and similar applications. The Canon has far more autofocus points, too: 5655 (to the A7 III’s 693 and the A7R III’s 425). However, the number of autofocus points alone is not enough to say whether the EOS R will have the edge in focus speed and tracking ability, so it’s important not to read too much into those numbers. You’ll need to wait for reviews from production sample EOS R cameras to know how its autofocus compares to other options on the market today. Judging from lack of a proper joystick and use of the LCD for autofocus selection on the Canon EOS R, we can guess that the Sony cameras are likely going to be more user-friendly in the field.

In terms of video, it depends upon your needs, but the Sony cameras are perhaps slightly ahead on paper. Although both Sonys are limited to 8-bit output over HDMI, the EOS R’s 1.74x crop factor for 4K video and the lack of 120 FPS 1080p leave it handicapped compared to other options on the market (including both of Nikon’s newest Z cameras as well, as shown in our Canon EOS R vs Nikon Z6 vs Z7 comparison article). However, keep in mind that the EOS R has dual pixel autofocus and a 180 flip LCD, so for certain applications, the Canon does come out ahead.

Aside from that, the Sony cameras both have better battery life than the EOS R. In turn, the EOS R has a higher buffer than the Sony A7R III and a slightly higher buffer than the Sony A7 III, although the buffer capacities cannot be directly compared between these, since Canon EOS R has significant limitations for continuous shooting. The 30.6 MP resolution, of course, sits between the Sony cameras’ 24.2 and 42.4 MP sensors. The A7R III has a higher shutter durability than either of the other cameras, and the EOS R has a higher resolution rear LCD.

Otherwise, although there are a few differences here and there, the cameras are fairly comparable. They weigh almost exactly the same, and they all include features like Wi-Fi, bluetooth, and focus peaking. More minor specifications may lean in one direction or another, but those are the most important ones.

Which One Should You Buy?

Given that the Canon EOS R is not on the market yet, and appears unlikely to ship until October of 2018, the simple answer is that it will be quite some time before we can compare these three cameras side-by-side and test them. If you need one of these cameras today, your only options are the Sony A7 III and the A7R III. That said, looking at the specifications, we can still draw some conclusions about the intended uses of each of these cameras, and which photographers might want to purchase one or the other.

First, the EOS R in some ways is like a mirrorless version of the 5D Mark IV (see our comparison). If you’re a Canon shooter with a collection of glass, and you were already thinking about a 5D Mark IV or other full-frame Canon DSLR, the EOS R is a mirrorless option worth considering – one that comes in a smaller and lighter form factor, along with a number of newer features. Although there are already ways to adapt Canon lenses to the Sony A7 series cameras, the EOS R is ahead in this regard. First, Canon’s new adapters include options for a drop-in filter or an extra control ring, which add a lot of flexibility to the system. And, perhaps more importantly, adapting lenses across brands is often prone to issues in areas like autofocus speed and general focus settings restrictions.

The Canon EOS R also looks ideal if you’re interested in a camera for vlogging, considering the exceptionally fast and smooth dual pixel autofocus during video, as well as the fully articulating screen. For some other video uses, though, the Sony cameras look preferable, since they don’t have a 1.74x 4K crop or just 60 FPS shooting at 1080p.

On paper, there is no denying that the Sony specifications are higher overall than those of the EOS R. There is simply no comparison with the dual card slots, longer battery life, IBIS, and twice higher FPS with autofocus (10 vs 5) – all of which are present even on the A7 III, which is $300 less than the EOS R. If you are starting a system from scratch and want the best possible specifications today, Sony is clearly the way to go (specifically the A7 III unless you need 42 megapixels for your work).

However, if you are a Canon shooter who is used to the menu system and the form factor of Canon cameras, the likely answer is to stick with the brand you already know. After all, the EOS R looks like it has very good ergonomics, including some new features like a touch-swipe bar to control various settings. And many users who have complained about the complexity of Sony menus are likely to appreciate Canon’s more intuitive system. That recommendation – sticking with the brand you already have – is especially true if you own a large collection of Canon lenses, or if you need one of the specific RF lenses Canon just announced with their mirrorless system.

I don’t think that the EOS R announcement is going to convince many dedicated Nikon or Sony users to jump ship, unless you can’t live without a fully articulating screen or Dual Pixel AF, but it’s enough to keep Canon users in the ecosystem. And the RF cameras have room to grow; with such a large diameter, comparable to the Nikon Z mount, we will likely see some very interesting Canon mirrorless lenses appearing in the future.