Sony's full-frame camera systems includes populist entries and specialized models alike. Its video line, the a7S series, has been defined by a purpose-built 12MP sensor, the perfect resolution for 4K video footage, since the first-generation model, but it's been close to five years since the a7S II debuted.

Today, Sony is unveiling the a7S III. Its image sensor is new, but maintains the full-frame 12MP design. It's the right resolution for 4K capture—Sony has decided not to play in the 6K or 8K space with this release.

The body design is very similar; Sony has made some changes here and there over the years, and has opted to use the same chassis as the a7R IV. It holds a much stronger battery than the a7S II, is protected against dust and splashes, and offers plenty of controls.

There are a couple of changes for video use. The LCD is mounted on a vari-angle hinge, so it swings out to the side of the body to face forward for monitoring. The 1.44 million dot screen supports touch input, and Sony has (finally) redesigned its menu system to be navigable by touch and to split settings between still and video modes.

An eye-level electronic viewfinder is also included. It's an all-new design, with nearly twice the pixels as we've seen in other high-end cameras. The 9.44 dot viewfinder leverages its resolution and improved optics to deliver a large, 0.9x magnification rating, rivaling medium format film cameras.

I've not yet had a chance to see it in person, but the benefits of a bigger, sharper EVF are clear. You'll get a better sense of your frame when setting up a shot, and it's a boon for work with manual focus lenses.

Locked Down or Handheld Versatility

Cinematographers working on serious productions are likely to lock the a7S III down on a tripod and attach accessories—matte boxes, focus pulls, external monitors, and the like. Its video specs are more than up to the task.

It's also a handheld camera for stills and video. The image sensor is mounted on a five-axis stabilization system, and autofocus has been updated to match others in the Sony system. It leverages phase and contrast detection, along with strong face and eye recognition, to keep your subject in focus—even when recording video.

There are dual card slots to record images and stills internally, and a full-size HDMI port for use with an external recorder. While no support has been announced, we expect popular external recorders to add Raw recording support—the camera sends out a clean 16-bit signal.

Internally it can record to SDXC or CFexpress media in either slot. It leverages the smallest of the three CFexpress card sizes, Type A, to accomplish this feat. Both slots support UHS-II, and most internal recording modes work with V90 or V60 rated cards. CFexpress offers much faster read and write speed, and is required for slow-motion footage at the highest quality setting.

Records at 10-bit Internally

Internally, the a7S III records video with 10-bit 4:2:2 color sampling in all modes. There are numerous compression rates formats available, including XAVC S Long GOP in H.264 or H.265, and a 600Mbps X AVC I All-Intra codec for the highest quality—and largest file sizes.

The camera records in 4K at up to 120fps, good enough for one-fifth speed slow-motion at 24fps. It pushes as far as 240fps at 1080p resolution. Autofocus is available, without any sort of compromise, even at the highest frame rates.

There are flat S-Log profiles available, as well as HLG options for delivery to HDR systems. If you opt for S-Log2 or S-Log3 you'll have 15 stops of flexibility when grading footage, good enough for scenes with bright highlights and subjects in shadow. The gamut settings match that of Sony's Venice cinema camera series.

The 12MP sensor design means that video is recorded without any sort of line skipping or pixel binning. The resolution matches earlier models in the series, but this one is read much faster. It's what allows for the higher frame rates, speedier focus response, and it also serves to reduce the rolling shutter effect.

There's another benefit—better video and image quality in low light. The sensor sports a BSI structure and gathers light into pixel wells that are larger than more typical 24MP cameras. It allows the a7S III to have a relatively low starting ISO 80, without sacrificing the high end; the camera can be set as high as ISO 409600.

It's also useable for projects where longer takes are a necessity. Heat is controlled, without the need for active measures like cooling fans. There's no in-camera recording limit per clip, and Sony states that the a7S III is good for a full hour of 4K recording at 60fps without worry of overheating.

Still capture is available at 12MP resolution as well, in your choice of Raw, JPG, or HEIF formats. HEIF offers a middle ground between lossy JPG compression, which limits the ability to edit shots, and Raw capture, which requires specialized software to process images.

Pricing and Availability

The a7S III is set to go on sale in September. It's priced at $3,499.99 as a body only for US customers. Canadians will pay more—Sony is pricing it at $4,799.99 north of the border.

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