Video Quality
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| The Sony a7 III is capable of impressively detailed 4K video capture, as shown in this screen grab from a 4K/24p video clip. |
The Sony a7 III's video feature set is impressively broad, giving users a wide variety of tools to aid in exposure, focus and more. Here's what we think are the main points to be aware of.
Key takeaways:
- The a7 III's 4K/24p footage is oversampled from 6K capture with no field-of-view crop, resulting in very detailed footage
- 4K/30p footage is oversampled from 5K video capture with a 1.2x field-of-view crop, is only slightly less detailed than 4K/24p
- Rolling shutter is well-controlled for all but the fastest pans and moving subjects
- Option for 1080/120p played back at normal speed as well as 120p capture slowed down in-camera to 30p or 24p for ready-to-use slow motion footage (S&Q mode)
- Includes picture profiles for capturing Log and HLG footage
- Includes zebra warnings and peaking for exposure and focus aids
- Autofocus during video works well with isolated subjects, but can be unpredictable and tap-to-track autofocus needs ergonomic improvement
Features overview
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As with most other Sony cameras these days, the a7 III is capable of shooting high-quality 4K video (the previous a7 II was only capable of Full HD). But it has a unique combination of features that make it one of the best interchangeable lens Sony cameras for video.
The newly redesigned sensor allows for quick readout, and for 4K/24p, the camera actually captures 6K footage using every single pixel on the sensor, and then downsamples that internally to 4K footage; this process gives incredible detail. Switch to 4K/30p and you end up with a 1.2x crop, but the camera is still oversampling, reading out 5K footage before downsampling to 4K. It's very slightly less detailed, but you'd be hard-pressed to notice it in the real world.
For a substantial discount, you get similar video quality as the a9 with all of the picture profiles present on the a7R III.
Sony's much-more-expensive a9 does the same oversampling in 4K, but it lacks picture profiles and the ability to record flatter 'Log' footage internally. The a7 III makes no such sacrifice, and recording Log footage for grading and editing in post helps you take more advantage of the camera's wide dynamic range. So for a substantial discount, you get much the same video quality as the a9, with all of the picture profiles present on the a7R III. It's a pretty sweet package.
The camera also captures 1080/120p footage natively (meaning it plays back at real time), and there's also a Slow & Quick mode that captures 120p footage and slows it down to 24p or 30p footage internally.
Lastly, we get a wide array of capture aids, including zebra warnings for exposure and focus peaking for those that prefer manual focus. The headphone and microphone jacks are also a nice touch.
Video quality
Our video test scene gives us a broad idea of how capable the camera is of capturing detail and dealing with moire. Because the a7 III uses its full sensor readout and then downscales, it should put up some very good results.
First of all, we can see that the a7 III looks all-but-identical to the a9, which also oversamples its 4K footage. The a7R III, on the other hand, uses pixel binning (grouping bunches of pixels together from its full 42MP readout), and can't match the 24MP sensors for detail. The a7S II, which was a 4K quality benchmark not long ago, falls behind and offers softer output. Switch the a7R III into APS-C / Super 35 mode, however, and it compares much more favorably.
As you use smaller portions of the a7 III's sensor, the quality predictably declines somewhat. The 1.2x crop comes from using 30p, and APS-C / Super 35 uses an even smaller portion of the sensor, so quality continues to suffer. But again, compared to the excellent a7S II, all modes of the a7 III contain impressive detail. The a7 III likewise holds up well against other competitors known for detailed 4K output.
There are other options that will give you better Full HD quality, though capturing 4K and downsampling to HD will give great results.
Switch into Full HD mode, though, and all the recent Sony's fall behind the older a7S II. This lack of 1080 quality compared to incredible 4K capture isn't as uncommon as you might think, but there are still other options that will give you better Full HD quality if you have no interest in capturing 4K, though capturing 4K and downsampling to HD will give great results.
We've also had a look at rolling shutter on the a7 III. It is far and away better than, the a6500, which suffers from very noticeable rolling shutter in 4K, and is about on the same level as the a9. With the a7 III, you may find it to be a problem for very fast video pans of sports and action or whip pans, but in every day shooting, it doesn't pose much of a problem. Switching to 4K/30p (1.2x crop) or Super 35 mode improves rolling shutter performance further.
Now let's look at some sample reels.
In the above video, you can see how impressively detailed the 4K/24p output is. The water, fountains and detail in the buildings in the background is all rendered nicely, and though there's some noise in the sky this is a fairly low light scene.
We were also curious about how the 1080 footage stacks up; it's been upscaled in this case, to give you an idea of how it will intercut with the 4K footage should you want to capture some higher frame-rate footage and intercut it with 4K. Bear in mind that you can also go about this in reverse, by capturing 4K and then downsampling to 1080 to intercut with the 1080/60p or 1080/120p footage.
And speaking of higher frame rates, let's take a look at a slow-motion demo reel.
For this test, we wanted to see what (if any) quality difference there was between shooting the a7 III natively at 1080/120p, and using the camera's S&Q mode. The latter captures footage at 120p and slows it down in-camera to either 24p or 30p, and we slowed down the natively captured footage using Final Cut Pro X on Mac.
As you can see, there's really not much in it between the two. We would personally recommend sticking to 120p capture so that you have normal-speed playback if necessary, whereas with S&Q capture you're locked into the slow motion version. Admittedly, if you're just looking to create a quick shareable clip, the S&Q mode is very handy.
Video autofocus
The a7 III's on-sensor autofocus system that works so well for stills should help it exhibit decisive and reliable autofocus in video, and it does - at least, some of the time.
Unfortunately, Sony's autofocus options in video still differ a little from what you can do when shooting stills. The tracking mode is an older algorithm, called Center Lock On AF. It requires a few extra button presses (after which you can tap to track, though it's not intuitive), and in general, isn't as reliable as we'd like. See our video demonstrating this here.
Your other options are leaving an AF area over your intended subject, which will work fine for subjects with predictable motion, but if you're shooting casual off-the-cuff video, the 'Wide' AF area works really well. It tries to automatically determine your subject, and prioritizes faces in a scene.
Ultimately, as you can see from the video above, both Center Lock On and Wide autofocus modes are capable of great results, but they're not as infallible as the tap-to-track implementation on Canon's latest cameras with Dual Pixel AF, like the EOS 5D Mark IV.
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