Video
As well as its high resolution sensor for stills, the Sony a7R II also offers an impressive set of specifications for video shooters. It's not quite as video focused at the a7S, which appears to be built from the ground up to offer excellent 1080p footage by shooting and downsampling 4K, but the a7R II is more flexible as a result.
Unlike any previous Alpha camera, the a7R II can capture 4K (UHD) internally. This can be achieved using approximately the full width of the sensor or a Super 35mm (roughly APS-C-sized) crop. Even in its cropped form, the camera is slightly over-sampling for UHD output (about 1.2x in each direction), which should mean less risk of moiré, regardless of crop mode.
In addition, the camera has all the video-friendly features added with the a7S: XAVC S recording, microphone and headphone sockets, Picture Profile color and gamma settings (including the S-Log2 profile with its super-flat logarithmic response, for added flexibility when grading).
In addition to this, the a7R II offers a range of supporting tools, including focus peaking and zebra to allow on-the-fly monitoring of focus and exposure, and time code to help synchronize the output in multi-device shoots.
Video Options
The a7R II mainly shoots in Sony's XAVC S format: the camera also supports the older AVCHD standard and MP4 shooting but these don't allow the higher quality options available in XAVC S mode. The XAVC S 4K mode offers 30p or 24p shooting at 100 or 60Mbps, while the HD options allow 50Mbps 1080 shooting at 60, 30 or 24p, and 720 shooting at 120p for compelling slow-motion footage.
The camera requires a SDXC card (speed class 10 or U1) to record HD video and it requires a UHS SDXC card rated to speed class U3 to record 4K footage internally.
Video Quality
This test is purely meant as a way of assessing resolution and how the camera is sampling its sensor. The good news is that, in all modes, the a7R II is sampling symmetrically, so you avoid increased risk of moiré that can come from line skipping.
However, it's pretty clear that the Super 35 4K footage is giving the cleanest, most detailed output. This isn't too surprising, given Sony's claim that Super 35 mode reads every pixel within the crop area, which means the camera is oversampling this region and downscaling, as an APS-C region of the 42MP sensor has more pixels than necessary for 4K. This is far better than pixel-binning or line-skipping. Ultimately, this means that full-frame 4K footage is slightly less detailed, and has a little more moiré, than Super 35 crop 4K. Further down this page we include some footage that cuts between full frame and Super 35 4K footage: this is the best way to judge whether the difference will be noticeable.
However, though you'll get the most detailed footage in Super 35 4K, you'll have to keep in mind that this crop mode shows significantly more rolling shutter than the full sensor width mode. Dan Chung, over at NewsShooter.com has looked into this in more detail.
Shooting in 1080p yields the opposite result: the footage from the full width of the sensor is significantly higher resolution than the output from the Super 35/APS-C region. The Super 35 footage is generally a touch softer and less detailed, so you'll only want to use it for the reach (and even then, you should shoot in 4K for dramatically better performance).
4K full width vs. Super 35mm
Click here to download the a higher-quality version
Above we take a closer look at resolution and dynamic range differences between 4K full-frame and Super35 video from the Sony a7R II. 4K Super35 (APS-C crop) footage shows considerably more resolution and dynamic range; the latter is evident in the lower noise levels, and better detail retention, in shadows of the Super35 footage. We confirm the lower noise levels in Super35 footage in our low light tests below as well.
S-Log2 was used to allow us to expose for the highlights; that is, keep skies from blowing to white. The flat tone curve of S-Log2 then boosts shadows to bring them to visible levels, despite severe underexposure.
Low Light Performance
Click here to download a higher-quality version (1080p)
Click here to download the 4K comparison at 4K resolution
We set up a 3.6 EV low-light scene to test the noise and detail levels of the a7R II under challenging light. The full-frame BSI-CMOS sensor of the a7R II means the potential for incredible low light performance, which certainly bears out with respect to stills, but what about in video? Have a look above. All footage was shot internally.*
We were surprised to find that 4K footage from the Super 35 region of the sensor is not only more detailed, but shows much better noise performance than footage from the full sensor width. This jives with the higher dynamic range of the Super35 footage from the Portland Japanese Garden above. The worse full-frame noise performance suggests the camera is sub-sampling in full width mode, instead of capturing the entire sensor area and down-sampling (which would give better results in low light, since the more light you collect, the better your footage). This of course means that, yes, the a7S II handily outperforms the a7R II in low light, as it samples its entire sensor area.
1080p captured from the full width is visibly better than the 1080p footage from the Super 35 region, but 4K full-frame downscaled to 1080p still appears a tad sharper than native 1080p full-frame footage. Since Super 35 4K is vastly superior to any other footage out of the camera, you'll want to try and stick to that, but if you want the best full-frame results, downscale 4K footage as opposed to shooting 1080p. In other words, you're better of shooting 4K no matter what your final output resolution is, though 1080p full-frame is a solid option if you need frame rates higher than 30p. You'll want to completely avoid 1080p Super 35, scaling down Super 35 4K if you need the reach.
Compared to Canon EOS 5DS R
Have a look below at a low light video shootout vs the Canon 5DS R, arguably the nearest competitor to Sony's high resolution offering. We look at full frame and Super 35 crop modes in both 4K and 1080p on the a7R II, and compare it to 1080p footage from the 5DS R.
Click here to download a higher-quality version
As we mentioned above, full frame 4K output from the a7R II does not appear to take advantage of the full frame sensor area; hence, though the a7R II downscaled footage looks more detailed than what the 5DS R offers, it shows no noise advantage. Both cameras aren't likely sampling their full sensor area. Furthermore, it appears that Canon's more sophisticated noise reduction makes its footage look cleaner.
However, because of Super 35 mode's oversampling on the a7R II, it looks far better than full frame footage from the 5DS R, with significantly more resolution and a little better noise performance. 1080p full-frame footage between the cameras is fairly similar, with the a7R II looking slightly sharper but also a bit noisier than the 5DS R. And with phase-detetion AF in video, to boot (next page)!
* We also shot all of this footage on an external Atomos Shogun recorder, and noted very little difference in performance to the internal 4K footage we're showing you here. This speaks highly of the encoding used in-camera, though there will certainly be situations where an external recorder will yield better, more gradable footage due to higher bitrates and chroma sampling.
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