Optical stabilisation tends to be better for telephoto shooting but a neat trick from the Sony is that, if you fit a stabilised lens to the camera, the system can automatically choose which to use for better performance.
As claimed, the Sony's autofocus is noticeably quicker than in the original A7, but the Canon still has the edge, at least when fitted with a lens that has a fast, ring-type ultrasonic system. It's the same story for continuous autofocus, where the Canon reigns supreme in its ability to stay locked on moving objects.
This makes the Canon preferable for sports and wildlife photos. Another performance boost is that the Canon has a maximum continuous drive rate of 6fps compared with the Sony's 5fps.
The Canon's evaluative metering mode is quite strongly biased to the active focus point (or points) that achieve autofocus but, even so, results are more predictable than from the Sony. In our tests, the Sony frequently blew highlights while trying to boost the brightness of shadowy areas in high-contrast scenes.
The actual amount of dynamic range is similar from both cameras but, when switched on, Canon's Auto Lighting Optimizer is a little more effective than Sony's D-Range Optimizer. When it comes to raw headroom for reclaiming highlights that are lost in JPEGs, both cameras have an impressive latitude.
Colour rendition tends to be a little warmer from the Canon, delivering richer and more flattering skin tones, as well as adding a touch of gold to landscapes. The flip side is that, when using auto white balance, the Sony is technically a bit more accurate.
For low-light shooting, both cameras do well to suppress noise at low to medium sensitivity settings. However, the Canon eases ahead at ISO 1,600 and beyond, giving cleaner-looking images that retain greater fine detail and texture.
One key aspect of performance that needs consideration is the viewfinder. The Sony's viewfinder is excellent for an electronic module, but doesn't compare well with the Canon's optical one. The Canon's viewfinder makes it easier to see even the smallest details, especially in very bright or dark areas of a high-contrast scene.
The Sony's EVF takes a 'what you see is what you get' approach to exposure settings and the application of exposure compensation. To see this on the Canon, or any other SLR, you need to switch to Live View and use the rear screen.
Canon EOS 5D Mark II vs Sony A7 II: Verdict
We could easily point to pros and cons for each camera and hedge our bets - but instead, we'll nail our colours to the mast. The Canon 5D Mk III is a better camera than the Sony A7 II.
Overall handling and the quality of the viewfinder are sufficiently better to make it worth the increase in size and weight. Metering in evaluative/multi mode is more reliable, and autofocus makes a better job of tracking moving objects.
When it comes to image quality, the Canon delivers more beautiful skin tones and gives a slight but very attractive warmth to colour rendition. It also creates cleaner, more richly detailed images at high sensitivity settings under low lighting conditions.
Back under the sun, the Canon's dynamic range optimiser is more effective for boosting shadow detail while reining in the highlights.
Don't get us wrong: the Sony A7 II is an extremely capable camera that's very well built and is rich in features. But the Canon 5D Mark III has the edge.
Canon EOS 5D Mark III
Sony A7 II
Canon 5D Mark III: 5 quick tips to get more from your EOS camera
Nikon D810 vs Canon EOS 5D Mark III comparison: full-frame DSLRs go head to head
Canon EOS 5D Mark III vs 6D: 14 key differences explained
Sony A7S II vs A7 II vs A7R II: which should you buy?
Sign up to receive daily breaking news, reviews, opinion, analysis, deals and more from the world of tech.