Conclusion
What we like What we don't
  • Excellent full-frame 4K footage at up to 60p
  • Only slight crop to 4K/120 mode
  • Excellent oversampled 1080 footage
  • 10-bit capture in H.265, H.264 or All-I H.264 gives workflow and grading flexibility
  • Log, HLG or Raw output options
  • Solid battery life
  • Choice of memory card format with most video recordable to SD or CFe
  • Nice viewfinder
  • Much-improved user interface
  • Option for HLG HDR photos using 10-bit HEIF format
  • Image stabilization, usable AF and good battery provides run-and-gun capabilities
  • Comfortable ergonomics
  • Full-sized HDMI socket
  • No out-of-camera DCI footage
  • Missing tools such as waveform display or shutter angle control
  • Video AF not quite effective as stills system and requires the screen to be tapped
  • 12MP stills appear low res, even at reduced sizes, compared with most modern cameras
  • Rear LCD isn't especially detailed

I've primarily used the a7S III as a video camera. It's clear both that video is where the bulk of Sony's effort has gone and that there's not a sufficient low-light benefit to make it worth spending this much money on a 12MP camera when less expensive models will produce more detailed images (even when downscaled to 12MP).

The a7S III can shoot lovely looking stills but they'd be more detailed (even if scaled down) if shot with other higher-res cameras.
Sony 24-70mm F2.8 | 1/80 sec | F2.8 | ISO 1000
Photo by: Richard Butler

In spec terms, it's obviously very impressive that such a small camera can reliably shoot 4K at 24, 30, 60 or 120p, without the need for a significant crop or loss of image quality. Those higher frame rates aren't likely to be the core way of shooting, but the option to shoot 4K for 1/4 or 1/5 speed slow-mo is impressive. The perfectly oversampled 1080 is excellent, too. For most users, it's the the ability to shoot all these modes in 10-bit and most of them in 4:2:2 with a choice of All-I or H.265 LongGOP that will be most useful: footage that's very flexible, both from a grading perspective and in terms of workflow.

We've found the revised menus much easier to navigate and less reliant on us memorizing where each setting can be found.

Beyond this, the greater emphasis put on heat dissipation and the much larger battery means you can rely on the Mark III to shoot for longer, in a way you can't necessarily do with other a7-series cameras.

Recent Videos

These higher-end capabilities raise our expectations for the camera. In particular it's disappointing not to see waveforms on a camera that's likely to be used as a standalone device. Similarly, if part of the a7S III's appeal is its ability to switch between different frame rates almost seamlessly, why is there no option to view exposure in terms of shutter angle so that you don't have to change shutter speed between modes?

Suddenly there's a serious competitor to Panasonic's S1H

These issues aside, the a7S III is hugely powerful producer of flexible footage supported by reliable autofocus, in-body stabilization and really solid battery life.

The ability to capture 10-bit Log 4K footage at up to 120p provides immense flexibility

The 4K footage itself isn't the most detailed – sampling roughly the same number of pixels as you plan to output isn't a recipe for optimal detail, even before you factor-in the impact on color resolution of using a Bayer sensor – and we're not convinced there are 15 usable stops of DR available, even in the Raw output. But Netflix's approval of the DCI footage from the similarly-sensored FX6 suggest it's more than good enough. Suddenly there's a serious competitor to Panasonic's S1H.

Compared to its peers

The Panasonic Lumix DC-S1H is one of the only stills/video cameras to take video anywhere near as seriously as the a7S III but It uses a very different approach: taking oversampled 4K video from a 24MP sensor, rather than adopting a ~4K sensor. This means its footage is more detailed than the Sonys but exhibits more rolling shutter and is limited to 30p unless you crop to Super35 mode, so it can't match the Sony's 60p and 120p ~full-frame capture. By contrast, though, the greater pixel count allows the S1H to offer anamorphic and open-gate 5.9K capture, which the Sony can't match.

The S1H footage is more detailed than the Sonys but exhibits more rolling shutter

In addition, the S1H has features such as a waveform display, an option to control shutter angle, timecode sync and, in our experience, better image stabilization. It also has a fan-cooled design that allows a level of dependability that Sony doesn't promise for the a7S III. That said, the Sony is smaller, has better battery life and much more usable autofocus, so it's not a clearcut win for the Lumix. Our sense is that the more pro-friendly S1H might fit more happily alongside other, higher-end cameras, whereas the Sony makes more sense for smaller one- or two-camera production outfits.

Sony a7S III scoring

Scoring is relative only to the other cameras in the same category. Click here to learn about the changes to our scoring system and what these numbers mean.

Sony a7S III
Category: Professional Interchangeable Lens Camera / DSLR
Build quality
Ergonomics & handling
Features
Metering & focus accuracy
Image quality (raw)
Image quality (jpeg)
Low light / high ISO performance
Viewfinder / screen rating
Performance
Movie / video mode
Connectivity
Value
PoorExcellent
Conclusion
The Sony a7S III is a powerful video tool that can shoot 4K footage at up to 120p (up to 60p with no crop), in a variety of 10-bit formats to provide plenty of flexibility in terms of both grading and workflow. It has dependable autofocus, in-body stabilization and good battery life to boost its run-and-gun credentials. Its 12MP resolution means it's less impressive as a stills camera but it's a hugely powerful choice for independent video producers.
Good for
Run-and-gun video, all manner of 4K productions
Not so good for
Landscape photography
91%
Overall score