Full-frame fury: Comparing Canon’s 5DS R and Sony’s A7R II

There is a debate happening in the camera world: If you had a choice between the Sony A7R Mark II or the Canon EOS 5DS, which would you pick? The online forum discussions can get a bit heated at times, but as far as we’re concerned, it’s all good: The more manufacturers battle for technical supremacy, the better it is for photographers of all levels.

Here’s why the two cameras are generating buzz. The Canon 5DS ($3,699, body only) and its doppelganger, the 5DS R ($3,899, body only but without optical low-pass filter) is, at 50.6 megapixels, the highest-megapixel full-frame DSLR camera you can buy. For anything higher, you’ll have to move up to an expensive medium-format camera or wait until somebody makes a new full-frame sensor. The Sony A7R Mark II’s 42.4MP backside-illuminated full-frame sensor doesn’t break any megapixel records, but this mirrorless camera ($3,299, body only) touts several achievements of its own: it is much smaller, has a completely different internal design, shoots at much higher ISOs (102,400 versus 12,800), and captures 4K videos. But the killer feature may be the A7R II’s ability to autofocus Canon lenses via an adapter.

As we are reviewing the production variants of the 5DS R and the A7R II, and given the heightened interest in the pair, we decided to take them into the field – grab stills and videos – and do a quick comparison. We’ll have full reviews of both cameras soon where we’ll discuss them in-depth, but if you’re an enthusiast photographer wondering right now about which to go with, here’s a brief overview on what you can expect. (You can also check out our hands-on tests of the 5DS and A7R II to get more first impressions.)

Same lens, different cameras

Typically, for comparisons, we’d shoot similar subjects using similar outfits, i.e., a Sony body with Sony glass and a Canon body with a Canon lens, preferably with the same focal length and aperture. Because of the A7R Mark II’s ability to use Canon lenses, we were able to also test both cameras using the same glass, a Canon EF 24-105mm f/4.0 zoom as well as an EF 50mm f/1.8 prime. Adapters are not new but what makes the A7R II unique is that it can autofocus a Canon lens; press the shutter half-way and you’ll see AF points light up, just as you would with a Canon body.

David Elrich/Digital Trends

This is a true breakthrough. It allows Canon owners to buy a Sony body and use most of their favorite lenses. However, there’s a big caveat: Not all EF lenses are compatible with Sony’s autofocus system. The 24-105mm worked fine with a Fotodiox Pro EF-NEX Auto adapter ($99) but the “nifty-fifty” did not; it would only work in manual not AF. In other words, anyone with a collection of Canon glass considering the A7R II must do their homework to ensure their favorite lenses are compatible.

For our test, both cameras were set to maximum resolution, using JPEG Fine and the respective video peaks.

Performance and use

The bulkier 5DS R (6 x 4.6 x 3 inches and 32.8 ounces with battery and card) feels just right with the hefty 24-105mm lens attached. Balance is good and it does not feel awkward. The A7R II, given its much smaller body (5 x 3.9 x 2.4 inches, 22 ounces), feels a little off-kilter when using the same lens. Not that we had any problems using it, but it does not feel as natural as the all-Canon outfit. The 5DS R optical viewfinder is much brighter and bigger than the A7R II’s electronic variant. Even though you can’t see the impact of changing exposure compensation or white balance, as you can with the electronic viewfinder, we preferred the 5DS R’s – it was just easier to use.

We shot a lot of static subjects such as trees and desert plants. When done we examined the images on a 27-inch monitor, checking out the results and pixel-peeping with extreme enlargements. Overall, we give the nod to the Canon rig but the Sony isn’t far behind. For most people, in our opinion, the difference between 50.6MP full-frame photos and 42.4MP isn’t so great.

Canon 5DS R

Sony A7R II

Check out the tree bathed in a dramatic sunlight after a rainstorm, for example. Yes, the Canon photo is a tad better but did it blow the Sony out of the water? Hardly. The same held true with other samples shown here.

If there is a difference, it is with low-light sensitivity. The 5DS R maxes out at ISO 12,800, compared to the A7R II’s 102,400. The Canon is an excellent performer and our sample subject held up very well to ISO 3,200, and even 12,800 was usable. The built-in optical image stabilization of the zoom did a fine job keeping things steady and sharp.

Canon 5DS R

Sony A7R II

The A7R II, however, reaches nosebleed heights. ISO performance is good at 3,200, 6,400, 8,000, and even 64,000. This is really impressive and if you’re a low-light shooter, using the A7R II with a wide-aperture prime will put you in photographer’s heaven. The A7R II has built-in five-axis image stabilization for any lens that’s attached, and we barely noticed any blur, so Sony gets a plus mark here.

The A7R II also holds a wide lead in video, hitting 4K 30p at 100 Mbps (XAVC-S format) versus 1080/30p for the EOS 5D SR. Canon execs have said the 5DS and 5DS R excel in still quality, not motion, hence the much lower video spec. Needless to say, if you want to capture high-quality videos to view on the big screen, or the option to scale from 4K to Full HD, the A7R II is the way to go.

Download the full resolution shots for the 5DS R and A7R II.

More megapixels or greater flexibility?

Back to our original question: If you have the cash, should you buy a Canon EOS 5DS/5DS R or Sony A7R Mark II? It depends, as there isn’t a black-and-white answer. The Canon takes terrific photographs with resolution and detail galore. If you have a comprehensive collection of Canon EF lenses and still photography is your passion (or your profession relies on it, like studio photographers) there’s really no reason to opt for the Sony with an adapter. And remember, not all EF lenses work seamlessly with the Sony AF system. That said, there’s a reason the A7R II is generating so much buzz. It’s a wonderful, versatile camera that takes beautiful stills as well as top-notch 4K movies, and has low-light capabilities that are world class. And it’s $700 cheaper, which certainly should factor into the discussion as you debate the two cameras.

Stay tuned for our full reviews.

Specs compared