Mirrorless compared: Nikon Z7 and Sony a7R III
Nikon has finally announced its first full-frame mirrorless camera, the Z7, and it probably won’t come as any surprise that it’s poised to take on the current high resolution mirrorless king: the a7R III. But, as closely as these cameras may appear on a spec sheet, there are some notable differences in addition to the similarities.
At a high level, both models offer the maximum resolution within their respective product lines, with the Z7 capturing 45.7MP while the a7R III captures 42MP. Each is also designed with both still photography and video in mind, with Nikon leveraging its new mirrorless platform to include video features not found on its DSLRs. Even their prices come in at a similar point, with the a7R III body retailing for $ 3200 while the Z7 lists for $ 3400.
On the following pages we’ll look at some specific comparisons between these two models to see where the similarities end and the differences begin.
Body and design
One of the things Nikon has done very well on the Z7 is to make the camera feel like… a Nikon. Its build quality is on par with the company’s mid-range DSLRs, it includes a large comfortable grip that should make most Nikon users feel right at home, it has well-placed buttons and includes as a joystick controller on the rear of the camera.
Sony’s mirrorless Alpha series has now gone through three generations of design and has reached a point where it’s feeling pretty mature. In particular, the a7R III gained a larger, more comfortable grip than earlier models and also includes a joystick controller on the back. But among our team the consensus is that the Z7 is more comfortable to use, not the least because Sony’s bigger grip is still far too small in height to fit most hands, causing increased fatigue over extended periods of use.
Both cameras claim to be weather-sealed, but the Nikon’s weather-sealing feels more substantial all around; It also includes seals around the battery door, something notably absent on the Sony.
The Z7 also includes a top plate information display, a feature carried over from Nikon’s DSLR designs, though now it’s an OLED panel instead of LCD; It’s something which may appeal to users moving over from a DSLR body.
We’re inclined to give the nod to Nikon in this particular comparison, though we realize that ergonomics represent a highly personal preference.
User interface
Nikon tells us one of its design priorities on the Z7 was to provide a seamless transition for Nikon users migrating from its DSLRs, and this is clearly reflected in the Z7’s user interface. The camera inherits its menu system directly from Nikon’s DSLRs, and the Z7’s menus are virtually identical to those on the D850, which we found generally easy to operate. In contrast, although Sony’s menus have evolved and are easier to navigate than in the past, they can still be a bit confusing or occasionally leave you searching for that one feature you know is hidden somewhere. Both cameras offer customizable ‘My Menus’, mitigating this issue.
Both cameras also include a rear touchscreen. The Z7 embraces its touchscreen, letting you use it for numerous functions including setting the AF point, interacting with the menu, and smoothly zooming and navigating through images in playback mode. It also enables a touch-friendly version of Nikon’s customizable ‘i’ menu, which lets you quickly change settings by tapping the screen. One curious omission is that the rear LCD can’t be used as a touchpad to control the AF point when holding the camera to your eye. Overall, however, we’re impressed with Nikon’s touchscreen implementation, which feels as though it’s an integral part of the camera’s design.
In contrast, the a7R III’s touchscreen feels like an ‘add on’. Sony’s decision to disable it by default only speaks louder to the issue that the touchscreen on Sony cameras is, currently, almost a nuisance. It doesn’t offer enough benefit to outweigh the negatives of accidental to touch operation.
Sure it includes a touchpad mode for moving the AF point with the camera is to your eye, but it’s cumbersome and unintuitive at best. Yes there’s the ability to tap on the rear screen to set the focus point but, again, it’s unresponsive and unintuitive at best, giving the sense that it’s been bolted onto the system rather than designed to be part of the user experience from the product’s inception.
Both cameras provide numerous options for customization, though we think most people will find the Nikon easier to pick up and use without spending a lot of time setting up the camera. However, the Sony certainly gets points for very deep features and customization options to meet your needs. There’s not a clear winner here – each provides advantages depending on how you plan to use the camera – but if we were forced to choose one overall implementation, it would be the Nikon.
Image quality
It’s hard to find fault with either camera when it comes to image quality as both are capable of delivering extremely high quality images when paired with good lenses, and from a practical standpoint the difference in resolution is negligible. Nikon tells us the Z7 uses a very similar sensor to the one found in the D850 (including its ISO 64 mode), and based on our experience so far we expect image quality and dynamic range performance to be similar to that camera. Of course, the a7R III is no slouch when it comes to dynamic range, either, performing similarly to the D850 despite having a base ISO of 100 and receiving a bit less light.
Generally speaking, we still prefer Nikon colors, though Sony has made significant improvements to its color science of late. However, Sony’s high ISO noise reduction is a step ahead, leaving behind a nice random noise pattern while Nikon’s JPEG engine can leave behind ‘rice grain’ artifacts.
We’ll be able to provide an in-depth comparison of image quality once we’ve completed our studio scene tests using Raw image files, however most users should be able to extract beautiful, high resolution photos from either of these cameras, particularly when working from Raw files.
Autofocus
Both cameras provide autofocus using on-sensor phase-detect autofocus systems. The Z7 features 493 phase-detect AF points with an impressive 90% horizontal and vertical coverage of the frame. It also features face detection technology plus body movement (designed to continue tracking a subject even if they turn their face away from the camera), and is rated down to -1EV with an F2 lens attached (-4 EV if you enable ‘Low Light AF’, albeit at the cost of much slower autofocus). Nikon also gets credit for its bright AF points which are easy to see in the viewfinder, compared to Sony’s grey AF points that can be difficult to see against, well, most backgrounds.
The a7R III has 399 phase-detect AF points, which cover a smaller area of the frame than the Nikon, but it also utilizes 425 contrast-detect AF points to provide greater coverage. It also includes Sony’s very effective ‘Eye AF’ system, one of our favorite features on the camera. Using Eye AF, the a7R III identifies and focuses on a subject’s eye, tracking it tenaciously if it moves within the frame. The Z7 doesn’t offer an Eye AF mode. The a7R III is rated to focus, with F2 lenses, at lower light levels than the Nikon (outside of Nikon’s ‘Low Light AF’ mode): an impressive -3EV in fact.
Although Nikon did a good job of translating its DSLR user experience to a mirrorless camera, one feature that didn’t make the transition is its 3D Autofocus system, which we consider best-in-class. Instead, the Z7 inherits a version of the AF system used by Nikon’s DSLRs in live view mode. Instead of simply placing an AF point over your subject and initiating focus, the Z7 requires you to press OK to enable subject tracking, and to press it again to change subjects. By comparison, Sony’s Lock-on AF provides a more seamless experience for subject tracking: like Nikon DSLR 3D Tracking, you simply place your AF point over your subject and half-press to initiate tracking. Eye AF even works in a similar way. This simple method of quickly selecting your subject on the fly is, sadly, completely missing from Nikon’s debut mirrorless, and that will undoubtedly impact fast-paced shooting with high demands on AF performance.
Overall, the a7R III wins here, despite the fact that Nikon has one of the best AF systems on the market in its DSLRs. If it can bring that system, or something similar, to its mirrorless cameras it may well change the equation.
Video
While Sony has a history of including a lot of video features on its cameras, video has typically been a secondary feature on Nikon’s DSLRs. With the Z7, that changes: Nikon is making a statement that it can do video, and do it well.
Both the Z7 and a7R III can record video up to UHD 4K/30p, as well as 1080/120p for slow motion (though the Nikon can only do this from a Super 35 region). One challenge common to both cameras is processing video from very high resolution sensors, though Nikon and Sony have essentially taken the same approach to solving the problem. Each camera can capture 4K using the full width of its sensor, but with limited sampling (line skipping on the Z7 and pixel binning on the a7R III). For best results in 4K, both provide the option to record from an oversampled Super 35 (APS-C) region of the sensor, which adds a crop factor to your focal length but results in very high quality 4K video.
Resolution isn’t everything, however, and the Nikon displays more rolling shutter in its full-frame 4K footage compared to the Sony. Both cameras offer Log gamma curves to support video shooters. In particular, Nikon has added its own Log gamma curve to the mix, and can output 10-bit 4:2:2 N-Log over HDMI. Internal recording is limited to 8-bit 4:2:0 at up to 100Mbps, and internal N-Log recording is not supported. In contrast, the a7R III supports internal Log capture using the S-Log2 and S-Log3 gamma profiles but only in 8-bit 4:2:0 color. HDMI output is also limited to 8-bit 4:2:2 signal, unlike the 10-bit found on the Nikon. The Sony offers an 8-bit implementation of Hybrid Log Gamma for capture and display on HDR TVs and monitors, which is particularly helpful because it’s not as extreme as other log profiles and, therefore, a bit more friendly with 8-bit capture. Furthermore, Sony’s HLG capture mode allows for perfect Raw histograms/zebras, so you can optimally expose your Raws.
Both models also offer an array of features designed to assist video shooters, including focus peaking, zebra warnings, and internal LUTs for use when shooting Log gamma (‘view assist’ on Nikon and ‘gamma display assist’ on Sony).
On the hardware side of things, both the Nikon and Sony include sensor-shift 5-axis image stabilization systems, as well as microphone and headphone jacks for recording and monitoring audio.
Thanks to on-sensor phase-detect autofocus, both cameras have very effective AF when shooting video. While we’ve come to expect excellent video AF from Sony cameras, this represents a significant step for Nikon and we’re very impressed. Video AF on the Z7 is among the best we’ve seen on any camera, dependably focusing on and tracking subjects, matching or even outclassing the a7R III. More importantly, the ease with which you can specify who or what you want to track on the Nikon Z 7 is far superior to what’s offered by any Sony camera, period.
We’ll call this a draw for now since it depends on your specific video requirements and workflow, but we will say that for ease of use, the Nikon Z 7 wins without question.
EVF and LCD
When it comes to electronic viewfinders, the Z7 and a7R III both deliver a high quality experience with 3.68M-dot OLED EVFs, though with minor differences in magnification (0.8x on the Nikon and 0.78x on the Sony).
However, despite the similar specifications, both EVFs are not created equal. The a7R III delivers the full resolution to the EVF in playback mode, but not when shooting, and resolution drops when shooting in burst mode. The Z7, on the other hand, maintains full resolution even while shooting, and uses a relatively complex optical design with aspheric elements and a fluorine coating. In its effort to provide a seamless experience to DSLR shooters, Nikon has created a bright, sharp display that provides an extremely lifelike experience. The Sony, though, has a slightly deeper eye-point, meaning its full extent can be seen from slightly (2mm) further away.
Both cameras also have tilting rear touchscreens, though the Nikon is the clear winner here with a 2.1M-dot screen vs. a 1.44M-dot screen on the Sony. As we’ve mentioned elsewhere, Nikon has also done a better job of integrating the touchscreen into the camera’s overall user experience, giving the impression that it was an integral part of the camera’s design from the ground up rather than a feature bolted on later.
Nikon wins this one.
Card slots and media
One of the more controversial aspects of the Z7’s design is Nikon’s decision to include a single card slot in the camera at a time when dual card slots have been considered an expected feature, particularly among premium models. The a7R III, in contrast, includes dual card slots with a variety of configuration options, including the ability to save all files to both cards for backup, using one card for overflow, or storing Raw files on one card and JPEGs on the other. Though it’s worth mentioning that Sony’s confusing interface for setting up the dual card slots might make you wish it only had one card slot to begin with.
Additionally, the two cameras use different card formats, with the Nikon relying on XQD cards while the Sony utilizes the more common SD format, though only includes support for UHS-II cards in one of its slots. Although Nikon may be somewhat forward-looking in going XQD-only (it tells us the camera will also support CFexpress media in a future firmware update,) if you’ve been using SD cards up until now you may need to budget for some additional memory along with the camera body.
Furthermore, the Z 7 doesn’t write all its files to the XQD card as fast as, say, a D5 – possibly due to the increased processing overhead of large 46MP images – hence the XQD experience on the Z 7 may not feel as finessed as with the D5. That may make you question the advantage of XQD on the Z 7, but it’s fair to say that, for now, XQD is more future-proof performance-wise than SD.
Lens mount and lenses
Nikon’s new Z-mount has a very short 16mm flange distance, slightly shorter than the 18mm distance on Sony’s E-mount, and both cameras have the potential to serve as ‘universal lens’ platforms for adapting older or third party lenses. However, while the E-mount has a relatively svelte 46.1mm diameter, the Z-mount is much larger at 55mm. In theory, this gives Nikon an advantage as it will be able to design fast lenses in the future without working around the constraints of the narrower E-mount.
At the moment Sony does have the advantage. Sony has been rolling out E-mount lenses for a number of years, and several third-party companies, including Sigma, have jumped on the bandwagon. There’s also a healthy ecosystem of E-mount lens adapters that have grown up around E-mount. However, the Z-mount has the potential to be the most adaptable mount ever thanks to its short flange distance, and in theory you could even adapt E-mount lenses to it. Unfortunately, Nikon isn’t sharing technical details of the mount, so third party makers will need to reverse engineer it.
Nikon has presented an impressive roadmap of Z-mount lenses, though only three have shipped to date. However, that doesn’t mean Nikon users will need to wait around for more lenses to appear. The company’s FTZ adapter will allow you to mount over 350 of its F-mount lenses to the system, including over 90 more recent lenses that will retain full functionality when mounted with the adapter. So, even without native Z-mount lenses, Nikon users should have plenty of options to choose from.
Sony probably comes out on top here today, but Nikon’s forward-looking Z-mount may give it a leg up in the future.
Extra features
While there are many differences between the Z7 and a7R III, many of them ultimately come down to different ways of implementing the same or similar features. However, each also has unique features not found on the other.
The Z7 includes built-in focus stacking and multi-frame mode, which provides an overlay of your existing frame as you take a second shot. It also includes an intervalometer for shooting time-lapse sequences and creating 8K time-lapse footage in-camera. This is a bit of a sore point for some a7R III users as there’s no built-in intervalometer and the camera does not have access to Sony’s PlayMemories store to add one.
While the a7R III lacks those features, it does have a pixel shift mode which combines four shots captured while shifting the sensor one pixel at a time. This can produce incredibly detailed images since it essentially eliminates the Bayer pattern on the sensor, ensuring full color data for every pixel, and also has the inherent noise and dynamic range benefits of combining four shots – though it has limited utility with moving subjects.
Performance
The Nikon Z7 can shoot 5.5 fps in continuous drive with live view updated between shots. If you need to shoot higher frame rates it’s possible to do so in High+ mode, which captures 8 fps in 14-bit Raw or 9 fps in 12-bit Raw. High+ maintains autofocus between shots, but locks exposure settings after shooting the first image. By comparison, the a7R III can shoot up to 10 fps with continuous AF/AE.
Speed matters, but so does a camera’s buffer, and the Z7 doesn’t have a large one. It fills up after 23 12-bit Raw files, 18 14-bit Raw files, or 25 fine quality JPEGs. Even though its fast XQD card can clear the buffer fairly quickly, you still notice the limit when you hit it. The a7R III’s buffer can store 28 frames of uncompressed Raw files or 76 frames when shooting compressed Raw, giving it an edge over the Nikon.
Of course, battery performance is important as well, and there are some big differences here. The a7R III uses Sony’s new NP-FZ100 battery, which has a CIPA rating of 650 shots, though in practice we typically see much better battery life than that. The Z7 uses Nikon’s EN-EL15b battery, an updated version of the D850’s battery which is capable of charging over USB. (Nikon says the older EN-EL15a will work in the camera as well, but won’t support USB charging.) Although we appreciate Nikon’s desire to keep a consistent battery format across cameras, there’s a cost to maintaining compatibility with earlier models: the Z7 has a CIPA rating of only 330 shots. We’ll get a better sense of how it performs in the real world as we continue testing, but the advantage definitely tilts in Sony’s direction, by a large margin in this case.
Conclusion
Sony’s early adoption of full-frame mirrorless means that it has owned the category until now, but the Z7 is a shot across the bow from Nikon. Overall, it’s matched very well against the a7R III, and some might argue that it even follows some of the Alpha’s design cues while still feeling distinctly Nikon-like in your hands. Both cameras are capable of delivering stunning image quality when paired with good lenses, so the main differences come down to other factors.
Nikon has done an excellent job of creating a good user experience on the Z7, despite it being a first-generation product. Ergonomics are generally quite good, the EVF is bright, crisp, and responsive, and the touchscreen is well integrated into the overall experience. It also steps up Nikon’s game with respect to video, including very good 4K video, support for 10-bit 4:2:2 N-Log via HDMI and potentially the best video AF we’ve seen on a mirrorless camera. What we really miss, however, is the 3D Tracking system found in Nikon’s DSLRs, which has consistently been best-in-class.
The a7R III has its advantages as well. In our opinion, it still has a better AF experience than the Nikon thanks to Eye AF and Lock-on AF, and its dual card slots will be a significant differentiator for a lot of users. It also boasts superior performance when it comes to continuous shooting and battery life. Sony has a much larger lineup of native lenses for its system, and the ecosystem of third-party adapters that has evolved around E-mount is impressive. Of course, Nikon’s Z-mount has a lot of future potential, but its decision not to share technical details of the mount means third parties will need to reverse engineer it.
The good news is that we now have two companies committed to full-frame mirrorless systems, and that should mean more competition and, ultimately, better products and more choices for consumers.
Articles: Digital Photography Review (dpreview.com)
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