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  • Alpha-better: Sony a9 versus a7R II

    Sony a9 versus a7R II

    The Sony a9 is a masterpiece of technology. Even if you have no intention of ever dropping $4500 to buy one, you have to admit that its key specifications are impressive. Aimed squarely at action photographers, it's much faster than the a7R II, with a more sophisticated AF system, but it can't match the older camera for sheer resolution.

    In this article, we'll be comparing the a9 and a7R II directly, looking in detail at exactly where their differences lie. For some photographers, the a9 might meet their needs admirably, whereas for others, the older a7R II might be just as good - or better. Read on to decide for yourself. 


    Perhaps the most fundamental difference between these two cameras is their sensors. The a9 offers a resolution of 24MP, putting it in the middle of the pack in terms of full-frame cameras' pixel-count.

    On the other hand, the 42MP sensor inside the 7R II offers the highest resolution of any Sony Alpha. In the entire full-frame market, it is second only to the Canon EOS 5DS/R when it comes to nominal resolution.

    Having so many pixels at your disposal is great for certain kinds of photography, like landscape and studio work, but of course it comes at the expense of large file sizes, and reduced operational speed.

    Our verdict: If you need the pixels, save some cash and buy an a7R II. If you need speed, read on...


    The a9, on the other hand, features a significantly lower-resolution 24MP sensor, but one that's been optimized for speed, rather than pure resolution. A maximum frame rate of 20 fps makes the a7R II look prehistoric, and 60 fps live view is available even during burst shooting. You don't need that kind of performance for landscapes, but for sports and action, it's extremely appealing. You can thank a stacked CMOS design, with built-in buffer memory for these tricks. In the image above, the sensor (1) sends data the signal processing circuitry (2) and on to a buffer (3) before pushing this data to the Bionz processor (4).

    But of course, a fast frame rate isn't useful without...


    ...a decent autofocus system.

    The a7R II impressed us when it was released, offering probably the best all-around AF performance of any full-frame mirrorless camera. Its 399-point on-sensor PDAF system is very capable, and allowed for very good autofocus with adapted Canon EF lenses, as well as lenses from Sony's own A-mount line. 

    The a9 takes things to a whole new level, offering 693 phase-detection points (represented above). Sony claims that autofocus acquisition has been improved by 25%, and eye and face-detection rates have improved by 30% compared to the a7R II.


    We've yet to formally test the a9, but impressions from our initial shooting are extremely favorable. While it's too early to say whether Canon and Nikon sports photographers will be tempted to make the switch, it certainly looks like the a9 can hold its own when it comes to capturing fast action.

    For Sony shooters though, if autofocus performance is a priority, the a9 is a clear winner.


    In terms of body design and handling, the a9 is a mixed bag when compared to the a7R II. Cosmetically, the two cameras are similar, but the a9 feels heftier and a little more substantial (it's barely any larger, but it is slightly heavier). The most important changes are in how the controls work and feel, and the addition of a much more streamlined GUI. 

    For starters, the buttons and dials on the a9 just feel nicer than they do on the a7R II. Less mushy, more 'clicky'. This, coupled with the reduced lagginess in control response makes the a9 feel more responsive than the a7R II even before you've taken a picture. The addition of an AF positioning joystick is another welcome improvement over the a7R II, which will be appreciated by all photographers - not just sports and action shooters.

    The a9's menu system is vastly improved compared to the a7R II - a long overdue change that we're very pleased to (finally) see.


    The a7R II's viewfinder is really nice, but the a9's is better. It offers greater resolution (3.7 million dots as opposed to 2.3M) and a higher framerate of 120 fps. This drops to 60 fps during continuous shooting, but a 60 fps refresh rate during 20fps shooting is nothing to sneeze at.


    The a9's rear LCD may sound like it only offers only a modest increase in resolution compared to the a7R II (1.44M dots compared to 1.23M) but there's been a move from a 640 x 480 pixels to 800 x 600, which should be appreciable. The difference is that the previous panel had red, green, blue and white dots at each position, whereas the new screen uses three dots per pixel (red, green and blue, with some green positions replaced by white).

    Furthermore, the addition of touch-sensitivity is a welcome (and again, overdue) upgrade compared to the older camera. Finally, it seems, Sony is getting the message that all the features in the world can't make up for a poor user experience.

    PC sync socket

    Well now, this is interesting... the action-oriented a9 has an ethernet socket, which makes sense for pro sports photographers, but it also has a PC sync socket, while Sony's high-resolution flagship studio camera, the a7R II doesn't?

    We'd be pretty confident that few, if any a9 buyers will ever use their camera's PC sync socket. Many won't use the Ethernet port either, but at least it's an indication of the intended user-base. To us, the addition of a PC sync socket is a pretty good indication that a higher-resolution sister model is on its way. The a9 represents the third ergonomic iteration of the full-frame Alpha series, so it makes sense that physically, any future a9-series models will share the same basic chassis. Is there a higher resolution a9R in the works? If Sony's past release schedules are any guide, we'd say it's a near-certainty.


    As well as being highly capable stills cameras, the a9 and a7R II both offer advanced 4K video specifications. In terms of sheer output quality, the a9 is likely to offer the best-looking footage, thanks to 2.4X oversampling from 6K with no pixel-binning, no line-skipping, and no crop factor. The incredibly fast readout speed of the new sensor means that there's little or no impact from rolling shutter, too.

    Both cameras offer headphone and microphone ports, plus HDMI and USB (the a9 is pictured above), although it's a shame that even the a9 is still limited to an old-style micr USB 2 port. Despite the incredible speed of the camera, we'll have to wait for a super-high-speed USB 3.0 interface.

    No S-Log

    Oddly though, the a9 lacks S-Log, and does not feature any of the Picture Profiles found on previous a7-series cameras (an example of what ungraded S-Log footage looks like is shown above). This limits its usefulness as part of a professional video rig, because it reduces the potential for grading footage in video editing software. Sony says this is because the a9 is offered primarily at stills photographers, but then why add 2.4X oversampled 4K video at all?

    Whatever the explanation, we're hoping that S-Log will be added via firmware. Unless, of course, its exclusion leave room for an a9S or some other, more video-centric model?

    Our verdict: If you can live without S-Log, the a9 will capture better full-frame 4K video. Oh, and there's something else it has to offer, too...

    Card slots

    The a9 offers twin card slots, one of which supports UHS-II media. This is an obvious improvement over the a7R II's single slot, and one that might prove to be a big deal depending on the kind of photography you do. Having two slots is always useful for redundancy if nothing else, and for mixed stills and video shooters, it's handy to be able to record movies to one card, and stills to the other. 

    We wish the a9 offered support for the much faster XQD card format, but we suspect that if it comes at all, XQD will arrive in the next generation of Alpha bodies. For now, two slots of any kind are definitely better than one. 

    New battery

    Oh happy day - we had almost given up hope. One of our perennial complaints about the a7-series was battery life. The weedy little FW50 inside the a7R II provides enough endurance for a couple of hundred stills, but for video work its low capacity of 7.7Wh meant frequent battery swapping during a typical day of filming.

    The a9 is introduced with a new NP-FZ100 battery, providing more than twice the capacity (16.4Wh). The boosted battery capacity, and a claimed 40% general reduction in power consumption compared to the a7R II should mean that the new camera will last a lot longer on a single charge.

    The introduction of a separate external 4-battery power pack, aimed at videographers and compatible with the a9 and all previous a7-series bodies is good to see, too.

    Final verdict

    The a9 is faster in all respects than the a7R II. Judging by our initial impressions, it should be a very capable tool for sports and action photography, certainly compared to its predecessor. Whether it can compete against the likes of Canon's EOS-1D X Mark II and the Nikon D5 is another matter of course, and we'll be testing that soon enough.

    From a more general user experience point of view the a9 is improved, too. Finally, a full-frame Sony camera with a menu system that doesn't make us want to scream, and a touch-screen! Wonders will never cease... 

    Is there anything the a7R II can do that the a9 can't? Not much, but the differences are important.

    Having almost 20 million more pixels means the a7R II can produce bigger prints, which might be a big deal for landscape and studio photographers. The a7R II's autofocus system isn't as good as the a9's, but it's still very good, and 5 fps is enough for most everyday shooting. For general photography (and more specialized high-resolution work) the a7R II will do the job admirably, for a lot less money than the a9. For now at least, the option of shooting in S-Log might make the a7R II a more attractive camera for video professionals too, despite the better resolution offered by the a9's oversampled footage. Its lower capacity battery life is still a limitation, but the release of the NPA-MQZ1K Multi-Battery Adaptor Kit will definitely help.

    Ultimately, for Sony shooters that really need speed, the a9 is clearly a better camera than the a7R II. The option of 20 fps continuous shooting with a 60 fps live view feed should prove addictive for anyone shooting fast action. The a9 also looks like a better camera for 4K video, thanks to 2.4X oversampling from 6K, and a new - larger - battery. 

    What do you think of the new a9? Let us know in the comments.

  • More videos added to product overviews and getting started guides

    Are you shopping for a new camera? Or just looking for some advice about how to use your current favorite model? We've just added several new informational videos to our range of product overviews and getting started guides, including guides to how to get started with the Fujifilm X-T20 and Nikon D3400.

    You can find all of our recent overview and getting started guide videos from the links below, and subscribe to our YouTube channel to ensure you never miss a new video!

    Watch our series of product overview videos

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