Introduction Sony's a7 IV is the company's latest enthusiast-targeted full-frame mirrorless camera. Its price and spec put it directly into competition with Canon's hugely likeable EOS R6.
The improvements to the Sony mean that both promise powerful combinations of image quality, autofocus and video capabilities. But which is the better camera?
Given that the majority of modern cameras are very, very good, it's unlikely to be a decisive victory overall, so we're going to look at the two cameras and their respective strengths in detail, to provide you with the information to work out which camera is best for you.
Image Quality
The most obvious distinction in image quality between the two cameras is the pixel count, and this makes exactly as much of a difference as the numbers imply. The Sony's 33MP sensor captures a lot more detail than the 20MP Canon can and the sharpening of its JPEG engine makes the most of this resolution benefit.
The Canon has a tiny edge at very high ISOs, with is exhibiting a little less noise even when scaled to the same output size. However, the difference is small enough that it's only really visible in side-by-side Raw comparisons.
There doesn't appear to be much of a difference in terms of dynamic range, with both letting you dig very into the shadows of your Raw files before noise starts to overwhelm the detail or appear too ugly. The Canon appears to be applying some noise reduction to achieve this, but the visual result is that the noise in the deep shadows looks slightly less sharp than in the Sony.
Both produce very attractive JPEGs and very good image quality, overall, but overall we feel the greater detail capture of the Sony is most significant difference between the two.
Autofocus
Both cameras have very powerful, very straightforward AF systems, and ones that get even better if you go into the menus and make a couple of adjustments to hide and override some of the legacy features that aren't really needed.
Both will find eyes and faces that are very small in the scene and both will track them with impressive persistence. On both cameras you can just tap on the screen to specify where you want the camera to focus or, with a little work, you can get both cameras to track whatever's under your AF point, letting you use the AF joystick and keep the camera up to your eye.
On the R6 this is a case of changing the menu option to let you specify where its tracking (and face/eye detection) should start focusing, whereas you need only select AF-C and one of the 'Tracking' AF area modes on the Sony. Both cameras let you customize the number of AF area modes available, to let you slim things down to a manageable number.
We've not had a chance to shoot both cameras side-by-side in groups of people, yet, but both have performed extremely well, individually. We'll update this article once we've done so, to make clear if one is better than the other, but both cameras do extremely well with minimal need for user input or camera setup. If your camera is more than about two years old, both the Sony and Canon will out-perform it.
Handling
The concepts behind the handling and operation of the two cameras are pretty similar: both have fairly substantial hand grips, dials for the forefinger and thumb, and comparable numbers of buttons. Both also have dials on the rear face of the camera, if you want to control a third parameter as you shoot. But in practice they end up being quite different to use.
The Canon EOS R6 has the larger, simpler and, based on a straw-poll of the DPReview office, more comfortable hand grip. The on-screen display of aperture, shutter speed and ISO can be tapped to change that parameter and its Q Menu places buttons for common settings in the same places those settings' icons appear when the Q Menu isn't active. This leads to a very simple experience that encourages use of the touchscreen.
The Sony a7 IV experience can tend to be a little more complex but also more customizable. There's a lockable dial on the top shoulder of the camera that defaults to Exposure Comp but can be reprogrammed to serve other functions. Meanwhile the Fn menu is totally customizable, letting you access much more obscure settings, if you wish. This and the main menu are touch operable but there's no touch control of settings during regular shooting.
Generally the R6 feels like the simpler experience but at the risk of needing to delve into menus if you want to access some of the more sophisticated functions. With a little setup, the Sony will give you near-instant access to the settings you most often use.
Viewfinders and screens
Both cameras offer 3. 69M dot OLED viewfinder panels, with the Canon appearing to offer its full resolution more of the time (you need to push the Sony into a more battery-draining 'high detail' mode to use the panel's full detail levels). Both also offer high refresh-rate modes that again impinge on battery life if you engage them.
The Canon viewfinder has optics that provide 0. 76x magnification, whereas the Sony's give a fractionally larger view, with 0. 78x magnification. Both have an eyepoint of 23mm, so should give a similar experience for wearers of glasses.
It's a similar story when it comes to rear screens: both have fully articulating touchscreens. The Canon's screen is higher resolution, with 1. 62M dots giving a resolution of 900 x 600 pixels, whereas the Sony's 1. 04M dot screen equates to 720 x 480 pixels. This gives the Canon a 25% boost in linear resolution.
Battery life
Sony adopted the large 16. 4Wh NP-FZ100 battery some years ago, and at a stroke resolved most battery anxiety issues around its mirrorless cameras. The Canon EOS R6 can't quite match the Sony for day-to-day endurance, despite its LP-E6NH battery having a comparable 16Wh capacity.
Standard testing gives the Canon a rating of 510 shots per charge using its rear screen and 380 using its viewfinder. The Sony, meanwhile, delivers 580 shots per charge using its rear screen and 520 using its viewfinder.
These CIPA-standard numbers are based on abnormally high use of flash and image review, so typically under-represent the number of images you'll actually get, but you should expect the Sony's 35% higher through-the-viewfinder figure to result in an appreciable improvement in battery duration, compared with the Canon.
These numbers are all pretty good, meaning battery life shouldn't be too much of an issue with either camera. If you shoot lots of video and do find yourself running through a battery, both cameras will let you re-charge over USB, with the Sony willing to accept power from most chargers, whereas the Canon appears to require a smarter, higher-current charger, such as a USB-PD spec device.
Images for HDR display
Both the Canon and Sony offer the ability to capture 10-bit HEIF images, rather than just 8-bit JPEGs. The most compelling reason to shoot these files is if you're trying to capture more dynamic range than usual, for playback on a high dynamic range TV, where it's useful to have more capacity for the additional tonal range.
The EOS R6 will only shoot HDR HEIF files, and encourages you to use Highlight Tone Priority mode to capture additional highlight information. Canon uses the 'PQ' curve used in the Dolby Vision, HDR 10 and HDR 10+ standards. It's not designed to work on conventional standard DR (SDR) displays, and the camera will let you generate conventional 8-bit JPEGs from your HDR HEIFs, if you need to share them.
By contrast, the Sony will let you shoot 10-bit HEIFs in any color mode and gamma curve you want, with a choice of 4:2:0 or 4:2:2 color resolution. This adds flexibility but also significant complexity, relative to the Canon. We'd mainly suggest using the Hybrid Log Gamma Picture Profile, which is widely compatible with HDR TVs and is supposed to be backward compatible with SDR displays, too.
Continuous shooting
Both cameras make big claims for continuous shooting but there are significant caveats in both instances. Overall, both cameras' autofocus systems mean they're pretty adept at action shooting, but they're not quite as geared-up for intense action shooting as their specs appear to imply.
The Canon promises most and probably deserves the bigger asterisk next to those claims. Its headline claim is the ability to shoot at up to 20 fps, but this requires that you use the electronic shutter mode, which is likely to distort your subject if it moves too quickly across the frame. Raw shooting drops to 12-bit mode (reducing the amount of dynamic range in the files) in electronic shutter mode. Mechanical shutter can shoot at up to 12fps (without a drop in bit depth), so long as the battery has more than 50% charge and some of the more processor-intensive features are disengaged.
The Sony has fewer restrictions for its 10 fps mode, but there's still plenty of small print. Again it drops to 12-bit when shooting continuous bursts and it can only maintain its full speed in the lossy compressed Raw mode, meaning less dynamic range and an additional risk of artifacts if you try to push the files too far. And, rather than seeing a live update, you are shown the image the camera has just taken, meaning you need to compensate if you're trying to follow action. Use the camera's lossless compression (or uncompressed mode, if you have loads of hard drive space you're determined to use up) and the continuous rate drops to the same 6 fps that the Canon offers.
We believe you're much more likely to see the distortion of the R6's electronic shutter in action images than notice the loss of dynamic range of the Sony, so that leaves it as a 12fps* vs 10fps* battle that we'd struggle to choose between, by the time we've taken resolution into account.
Video
The two cameras offer similar headline specs: with 10-bit 4K capture at up to 60p, but there are some significant differences, the more you dig in.
The Canon EOS R6 shoots video using a slightly cropped region of its sensor (the EOS 1D X III shoots 4096 x 2160 video from the full width of its similar sensor, but the R6 chops the edges off this, to deliver 3840 x 2160 UHD 4K). Its video looks good and has moderate rolling shutter (around 30ms in 30p mode and 15ms in 60p mode).
The Sony a7 IV shoots 4K footage at up to 30p using the full width of its sensor. This means 7K capture, for footage that approaches the maximum level of detail that can be conveyed in 4K footage. Moving to 50 or 60p capture means applying a pretty significant 1. 5x crop, though, making it harder to achieve wide-angle shots and coming with a noise cost. Rolling shutter is little better than the Canon, though: ~26. 5ms for 30p capture and ~13ms for 60p mode.
The Canon EOS R6 can overheat if used extensively (for stills or video), which can limit the duration of its recordings, it can then take a while to cool enough to allow additional recording. It's also limited to a maximum clip length of 29 minutes, 59 second per clip. The Sony has a menu option to over-ride its temperature limits, at which point it can record near unlimited footage. It does not have a limit for individual clips, other than card capacity.
Video
The Sony's autofocus system is very much like the one used in stills (though you'll have to tap the rear screen if you want to start AF tracking). The tracking itself doesn't feel quite as unerringly dependable as it does in stills, but it still works very, very well. The EOS R6's video AF seems similarly robust: tracking objects around the scene in a confident manner.
In terms of video tools, the Sony edges ahead, though. It offers a display that indicates what's within depth-of-field, helping you to choose and adjust aperture, as you shoot. It's also got a feature that crops and upscales footage to compensate for the focus breathing of a selection of Sony's own-brand lenses. There's also the peaking and adjustable zebra exposure indicators you might expect. The a7 IV has a dedicated stills/video switch and lets you decide which settings do and don't carry over when you jump between modes.
Another detail in the Sony's favor is the adoption of a full-sized HDMI socket, rather than the less dependable Micro HDMI connector on the Canon.
The Canon also has a good degree of separation between stills and video shooting and it also offers focus peaking and zebras. Generally the Canon offers fewer options, but generally does so in a sensible manner: for example, you can only shoot 10-bit footage in Canon Log or HDR modes, where you'll benefit from the extra information, rather than Sony's 'do whatever you want' approach. We've also found the Canon's image stabilization to be more effective than the a7 IV's, particularly in video.
Lenses
Sony was the first company to offer a modern full-frame mirrorless camera, and has also been willing to share the details of its E-mount with other lens makers. As a result, there's a much wider array of lenses designed for it than any other mirrorless mount. This includes options such as Tamron's excellent and comparatively affordable 28-75mm F2. 8 G2 and Sigma's range of compact primes.
The EOS R6 can't come close to competing, in terms of native lens availability, but you can buy an adapter to allow the use of almost every one of the company's 'EF' DSLR lenses, and the third-party optics that were available for that mount. This adapter is quite deep (it essentially adds an empty mirror box in front of the camera, to create enough of a gap between the sensor and the lens mount), but it's a great option if you have Canon SLR lenses. EF lenses can also be adapted onto the Sony, but the performance tends to be less predictable.
Another consideration is that Canon's RF system doesn't appear to embed any lens profile information into its Raw files: meaning that your lenses may appear distorted unless you use Canon's own Digital Photo Pro software, or wait for your software vendor to profile each lens.
Conclusion
The Sony a7 IV is the company's first enthusiast model to be launched since Canon, Nikon and Panasonic joined the full-frame mirrorless melee. Looking through, detail by detail, it appears to do enough to pull Sony back ahead of what has been our favorite camera in the the sub-$2500 part of the market. There are no knockout punches landed against a camera as good as the R6, but the a7 IV keeps landing the blows: higher resolution, slightly longer battery life, fewer restrictions and more support tools in video.
The judges' decision has to go the way of the Sony, then, with the scoring reflecting the much wider availability of lenses for the E-mount. But even then, there's the risk of a split decision.
And even after that, the viewers at home, particularly ones with an existing collection of EF-mount lenses may well dispute this result. The a7 IV walks away with the title belt, but the R6 is likely to be recognized as a worthy fighter by many in the audience.
. dpreview.com2021-12-16 17:00
