Sony a7R II versus a7 II: Eight key differences
 |
Sony’s a7-series marked the debut of full-frame mirrorless, and Sony still dominates this market with its a7S II, a7 II and a7R II. Sony has developed a reputation for rapid development cycles, and since they all look basically the same, it can be hard to figure out the differences between its current a7-series offerings.
The higher resolution a7R II costs almost twice as much as the a7 II, and in this article we’ll be explaining why. So join us, as we take a detailed look at the major differences between the Sony a7 II and the a7R II.
Resolution
 |
The a7R II was the first camera to offer a BSI-CMOS full-frame sensor, when it was released last year. The additional resolution compared to the a7 II makes it possible to print significantly larger images, and of course there’s lots of scope for cropping.
Like all of the cameras in Sony’s a7-series, the a7 II and a7R II are both built around full-frame CMOS sensors, and the a7 II uses the same 24MP as its predecessor, the first-generation a7. The a7 II’s sensor is perfectly capable, and can deliver excellent image quality, but it’s not a patch on the 42MP sensor in the a7R II.
The increase in resolution isn’t the only reason we say that. The flagship a7R II features a back side illuminated (BSI) CMOS sensor, which offers significantly greater dynamic range, far better low light performance, and features 399 phase detection autofocus points (more on that later).
Dynamic range
 |
The Sony a7R II boasts a significantly higher base ISO dynamic range than the a7 II, and this relationship is maintained until the two camera’s highest ISO settings. Both are superior to Canon’s EOS 5D III. Source: Bill Claff
The a7 II’s older 24MP sensor lags behind the newer a7R II in terms of dynamic range at all ISO sensitivity settings. At the all-important base ISO (ISO 100 in both cameras) the difference is a little under one stop. The gap closes a touch from ISO 200-400 but widens again thereafter.
Very few things ignite (or should that be ignorate…?) quite as much argument on DPReview forums and comment sections as dynamic range, but the basic fact is this: greater dynamic range, especially at base ISO, means greater latitude for exposure adjustment in Raw mode. In cameras that offer very good dynamic range, like the a7R II and Nikon D810 (just to take two examples) this effectively negates the requirement for graduated neutral density filters, and greatly expands a photographer’s ability to capture a full tonal range in a single exposure.
The a7R II is better than the a7 II in this regard, but both are better than full-frame DSLRs in this class (we’ve plotted the EOS 5D III in this graph, from Bill Claff), which are also limited by relatively high levels of noise in shadow areas. This can become problematic when Raw files are manipulated too heavily.
Read more about the a7R II’s sensor performance
ISO sensitivity / low light
 |
Even at ISO 12,800, the a7R II’s Raw files contain bags of detail, and more dynamic range than the a7 II. When normalised at 24MP, the higher-resolution a7R II also offers superior perceptual detail and lower noise levels than the a7 II. As well as image quality, the a7R II scores over the older camera again in terms of low-light AF performance.
In the good old days, it was generally believed that the more pixels you packed onto a sensor, the noisier the images you’d get out the other end. These days of course we’re much more enlightened, and as we all know, the idea that more pixels = more noise isn’t necessarily true. And everybody is happy now because we all understand that pixel-level noise isn’t the whole story, and the time we used to spend arguing about such things on the Internet we now spend with our families, when we’re not out in the sunshine taking photographs.
Only some of that last sentence is true, but what is true is that despite having almost twice as many photo-sites as the a7 II, the 42MP a7R II offers superior high ISO image quality. When files are normalized to 24MP and viewed side-by-side, the a7R II offers at least one stop better perceptual image quality in terms of Raw noise levels, and in terms of detail retention it’s more like two stops better than its 24MP cousin.
Part of the reason for this performance gap is simply the fact that the a7R II’s sensor is a couple of years newer than a7 II’s, and sensor technology (especially at Sony) moves quickly. But fundamentally, the sensor in the a7R II is of a very different design. BSI-CMOS sensors move a lot of per-pixel electronics to the back of the sensors, out of the way, so they’re more efficient when it comes to converting photons into usable signal. As such, the a7R II isn’t just better than the a7 II, it’s better than almost every other full-frame camera we’ve ever tested. Up to around ISO 25,600 it even holds its own (when files are normalized at 20MP) against the Nikon D5.
Shutter
 |
Another benefit of BSI-CMOS sensors is the extra room afforded for more sophisticated circuitry – in the case of the a7R II that means faster readout circuitry. This allows the camera to record high frame-rate video (more on this shortly), autofocus faster than any comparable full-frame mirrorless camera (again, more shortly), and also to offer a fully electronic shutter.
Shutter-induced vibrations plagued our experience of using the original a7R, and have proved a serious headache in several other high-resolution cameras, including the Nikon D800-series. The a7 II and a7R II mitigate these issues with an electronic first-curtain shutter feature, but the a7R II also offers a totally electronic shutter option that comes with an almost negligible penalty in terms of additional noise (a traditional side-effect of electronic shutters).
We don’t recommend shooting with the fully electronic shutter option all the time, because there is the risk of some rolling-shutter distortion (i.e. if you’re panning to follow a fast-moving subject). But it is extremely handy for situations where you want to be discreet, like a performance space or a wedding ceremony.
Video
 |
The a7R II is a 4K-capable camera with a raft of high-end features, intended to appeal to professional videographers just as much as stills shooters.
The a7 II is increasingly looking like the odd one out in Sony’s current a7-series lineup, due to its lack of a 4K video capture. Of the two cameras, the a7R II is significantly more capable for shooting video, thanks not only to the addition of 4K, but numerous other features aimed specifically at the needs of professional filmmakers.
These include an oversampled Super 35mm (~APS-C) crop mode for 4K, internal recording in both HD and 4K modes and the super flat S-Log2 profile, for additional flexibility when it comes to grading footage.
The quality of the a7R II’s footage blows away the a7 II. Not only can the older camera not record 4K video, but its HD footage is softer and less detailed than the full-frame 1080 output of the a7R II. Interestingly, while the a7R II delivers superior quality 4K footage in its oversampled Super 35mm crop mode (notwithstanding a higher risk of rolling shutter), it gives much more detailed 1080 video when using its entire sensor. But the basic takeaway here is that regardless of the resolution or crop mode, the a7R II delivers better-looking video than the a7 II.
Autofocus
 |
When combined with continuous focus, Eye-AF is a great feature for capturing portraits – especially of kids that won’t stay still.
The a7 II uses the same AF hardware as its predecessor the first-generation a7, but Sony claims that autofocus performance has been improved by around 30%. In our testing we have no reason to dispute this figure, and in everyday use the a7 II’s AF is more than capable of keeping up in most situations.
The a7 II’s autofocus might be perfectly acceptable, but the a7R II is in another league. Both cameras use a ‘hybrid’ system which combines on-sensor phase-detection pixels with conventional contrast-detection but with more than twice as many phase-detection AF points as the a7 II, and the ability to focus third-party lenses (later added to a more limited extent to the a7 II via firmware) the a7R II’s AF specification impressed us greatly when it was first announced.
While it can’t keep up with the action as well as the market-leading 3D AF Tracking system found in Nikon’s current DSLRs, the a7R II’s ability to find and track an eye in Eye-AF mode for example is incredibly useful for wide-aperture portraits, and low-light AF reliability with fast lenses is almost a match for the best DSLRs.
That’s the good news – the bad news is that there’s still no way to position AF point by touch on either camera, and the a7RII and a7 II’s control and menu ergonomics make it annoyingly tricky to find, set and master their extensive autofocus settings.
Performance
 |
In terms of autofocus, the a7R II roundly outperforms the a7 II but when it comes to general operational speed it is markedly more sluggish in some ways. Image review especially can be very frustrating, as the a7R II’s huge files (made even larger if you select uncompressed Raw) can take several seconds to become available to review and zoom to check focus after they’ve been shot. When capturing sequences of images, the a7R II gives the kind of buffer-clearing times that we’ve not been used to since the early days of digital DSLRs. And we don’t say that in a nostalgic way.
The a7 II isn’t exactly a speed champion when it comes to processing speed, but it’s a little more nimble than its 42MP cousin.
Battery life
 |
Although both the a7 II and a7R II have relatively poor rated battery life, it is possible to charge the cameras over USB, and you can continue shooting while they’re charging.
With a CIPA-rated battery life of 350 shots, the a7 II offers greater endurance than the a7R II, which clocks in at a mere 290 shots per charge. But it’s a bit of a stretch to call 60 hypothetical exposures a ‘key difference’ in battery life. Honestly, they’re about in the same ballpark, and both are pretty poor. Both the a7 II and a7R II offer significantly less endurance than equivalently-priced DSLRs at 350 shots and 290 shots per charge, respectively (CIPA standard in both cases).
The a7 II has a better CIPA-rated battery life than the a7R II, but endurance in heavy real-world from either camera varies from just ok-ish to downright terrible, depending on things like the ambient temperature and the amount of video you end up shooting. We’d strongly recommend taking at least one spare battery out with you when working with either camera, but if possible, take a couple. Ideally, take several. Pop round and borrow a couple of ours. We trust you.
The somewhat lower quoted battery life of the a7R II can be explained by its more power-intensive 4K capture mode, but even if you’re mostly shooting stills and keeping image review to a minimum, don’t expect to get through a busy day’s shooting with either camera without changing your battery at least once. The good news is that both cameras feature in-camera USB charging and can still be used while charging. This might not help much if you find yourself in the middle of nowhere, but could be a life-saver when shooting at an event or in a studio.
In summary
 |
It should be obvious if you’ve read this far that the Sony a7R II is a significantly more capable camera than its stablemate the a7 II. They might look identical, but a quick run-down of just the major feature differences makes the distinction obvious enough: more pixels, 4K video, a vastly more capable autofocus system, fully electronic shutter, and more complete support for third-party lenses.
Whether these differences justify the enormous increase in price over the more basic a7 II is of course something that you have to decide for yourself. If you’re primarily or exclusively a stills shooter and you don’t have much need for continuous autofocus, the a7 II might suit you just fine. Its 24MP sensor isn’t the best around, but it’s not bad, and its 5-axis image stabilization system is very useful when shooting hand-held in poor light or at long focal lengths.
All this being said, if you’re new to the Sony a7 system, the a7 II doesn’t bring much to the table that you can’t find duplicated or outmatched in other, competitive DSLR models. The a7R II, on the other hand, offers some unique features that we suspect will make it distinct from competitive DSLRs for some time yet.
- Read our full Sony a7 II review
- Read our full Sony a7R II review
Want to compare more cameras? Click here
Did we miss anything? Let us know in the comments.
Articles: Digital Photography Review (dpreview.com)