Video-first creators using the Sony full-frame camera system adore the a7S series for its native 4K sensor, exceptional low-light performance, and compact form factor. The third-generation a7S III ($3,499.99, body only) ups autofocus performance for both stills and video, reduces rolling shutter, and supports 120fps capture at 4K. Along with other upgrades, there are compelling reasons to upgrade if you're still using an a7S II. Hybrid creators with a video-first mentality will be pleased with the camera's versatility, but pure cinematographers may be better served by the Sony FX3 ($3,899.99).
The Video-First a7
Sony's full-frame camera line is diverse. Its a7 models cater to enthusiasts and pros, the a9 series is there for high-speed stills, and the a1 is for creators who demand uncompromising performance for both stills and video, without any compromise in speed.
Despite the delineation in the model lines, there's plenty of overlap in function, handling, and tech across the full-frame series. The a7S III shares its basic body design with the 60MP a7R IV, and controls are fairly uniform across the line.
The form factor is typical for a stills camera. An integrated handgrip and an eye-level viewfinder are included. The big difference is the rear LCD—with the a7S III it swings out to the side and faces forward, where other a7 cameras only offer upward and downward tilt.
Similar Products
Panasonic Lumix DC-S5
Sony Alpha 7S II
Blackmagic Pocket Cinema Camera 6K
Sigma fp
Nikon Z 6 II
Panasonic Lumix DC-S1
Sony a7 III
Canon EOS R6
Sony a7C
Sony a7R IV
Canon EOS R5
Nikon Z 7 II
Panasonic Lumix DC-S1R
The Sony FX3 is there as an option for pure video use. It omits the mechanical shutter and EVF included with the a7S III, adds active cooling for long-form recording, and has multiple mounting points for accessories—so you don't have to add a camera cage. Despite not being an a7 model, the FX3 works with all of the same FE lenses.
Handling and Controls
The a7S III is the same general size and shape as most other full-frame mirrorless cameras. It measures 3.8 by 5.1 by 2.7 inches (HWD) and weighs about 1.4 pounds without a lens. It's finished in basic black, with magnesium alloy construction and internal seals to withstand dust and splashes.
The handgrip is the same as you get with the a7R IV and a9 II. It's deep, with an indentation that acts as a finger rest. The body is comfortable to use with big telephoto lenses, but still light enough to use with a wrist strap and a light prime if that's more your style.
The grip includes a control wheel, and Sony puts the shutter release and on/off switch at its top. Record and C2 buttons sit behind it on the top plate, along with lockable dials to set the shooting mode and EV compensation. The rear control dial rounds out top plate controls—it rests naturally under your thumb.
The rear plate includes all the expected controls—a dial-direction pad hybrid used primarily for menu navigation, a dedicated joystick to set the autofocus point, and AF-ON, AEL, menu, and playback controls to round things out.
The on-screen interface includes controls, too. You can interact directly with the touch screen—Sony has finally updated its menus to work via touch. They're also a bit better arranged, with a three-column layout and some color to set different sections apart. The camera does a lot, and the menus are dense, so you'll still need to take some time to get acquainted. A customizable My Menu page is included, and adding your most-used functions will make your life easier.
The touch LCD is a 1,440k-dot panel with adjustable brightness. If you're using it to monitor video on a bright day, you'll want to turn on the Sunny Weather setting. It's a little less than what you get with the Panasonic S1H, though. Panasonic's camera uses a different lens system, L-mount, but supports 6K capture and includes a 2,330k-dot display, a bit better for use as a monitor, especially if you're focusing manually.
Conversely, the a7S III's eye-level viewfinder is second to none. Its magnification is the highest you'll find in this type of camera, 0.90x. The EVF isn't just big to the eye—its extremely sharp (9.4 million dots), and it shows a smooth image with accurate colors.
Z Battery and Full-Size HDMI
The a7S III sports a full array of accessory ports. Both USB-C and micro USB are included and serve a variety of purposes including file transfer, charging, webcam, and tethered control. A full-size HDMI port is there for use with external monitors and recorders. The large connection is less prone to breakage than the tiny micro HDMI ports that are more common on hybrid cameras. Uncompressed output for higher-quality compressed and 16-bit Raw video recording is supported via HDMI.
External audio is supported, too. The 3.5mm microphone port is built in, and there's also a 3.5mm headphone connection for monitoring. Digital microphones are supported via the hot shoe, and you can add an adapter for XLR microphones.
The Z series battery is a big upgrade over the W cell used by the a7S and a7S II. It provides nearly twice the life for stills, around 600 shots based on CIPA testing standards. You'll likely get more, and certainly will if you take advantage of 10fps continuous drive.
For video, expect about 95 minutes of recording time. I didn't run into overheating issues, but it can be a concern if you're recording longer-form clips—longer than twenty minutes—in hotter environments. The FX3 is a better camera for this type of work; it adds active cooling fans, so you won't have to worry about heat.
Bluetooth, NFC, and Wi-Fi are included for wireless transfer and remote control. The a7S III works with Sony Imaging Edge Mobile, a free download for Android and iOS devices.
Two memory card slots are included, both with support for either a UHS-II SDXC or CFExpress Type A memory card. Most camera functions work with SDXC memory, but you will need to invest in CFExpress cards if you want to capture slow-motion footage at the best quality.
Tracking Autofocus for 10fps Imaging
The a7S III focuses quickly and identifies subjects with serious acumen. It supports face and eye detection for people and pets, and tracks subjects with tenacity. Phase and contrast focus covers most of the sensor, giving you freedom to frame subjects off-center.
It's an effective camera for capturing action. It tracks subjects and fires off Raw, JPG, or HEIF photos at a brisk 10fps. The smaller files, sizable buffer, and support for ultra-fast memory allow for longer continuous bursts at a time. The camera rattles off better than 200 Raw+JPG pairs at 10fps without slowing down when using 300MBps Sony Tough SDXC memory.
The Real Time Tracking function in the autofocus system isn't brand new, but this is the first a7S model to include it. It's better at keeping up with a subject, and much easier to use than the older Lock-On Tracking function. You don't need to hit extra buttons to start or stop, or turn on face and eye detection—it's seamless.
Tracking works in continuous focus (AF-C) only. If you're using the camera for single-point focus you'll still enjoy the same level of subject recognition, but the focus point won't follow a subject as it moves through the frame.
For stills, all of the autofocus features work with native lenses from both Sony and third parties like Sigma and Tamron, as well as Canon EF lenses paired with the Sigma MC-11 adapter. The MC-11 delivers stills focus performance that's on par with native glass.
The same isn't true for video, though—adapted EF lenses are manual focus only, something to keep in mind if you use non-native lenses. Sony FE and native third-party E-mount lenses work fine, though—it's only a limitation with adapted EF glass.
Stabilized 12MP BSI Sensor
It's the full-frame, 12MP image sensor that sets the a7S III apart from competing cameras. Entry-level models are usually closer to 24MP resolution, and exotic high-resolution sensors have settled in around 50MP. The 12MP BSI design doesn't capture as much detail, but has a very wide ISO 80-409600 sensitivity range, and controls noise better at high ISOs than cameras with more pixels.
It's also stabilized, using Sony's tried and true five-axis IBIS system. Jitters and jumps are removed from handheld video and you'll be able to net longer handheld exposures for imaging. It's beneficial when you just want to get a little more light for a streetlamp-lit portrait, and works just as well for long-exposure photography without the aid of a tripod. It's quite possible to get 1/4-second and 1/2-second shots without the aid of a tripod.
See How We Test Digital Cameras
The a7S III supports JPG, HEIF, and Raw imaging. It's capable of capturing Raw+JPG and Raw+HEIF simultaneously, too. Photographers are well familiar with the JPG format, an 8-bit file that's processed and ready to share, and the uncompressed or lossless compressed Raw format. HEIF files sit between them in quality—they're still compressed and processed, but the 10-bit format provides a bit more room to edit, and a higher-quality image than JPG. It's not as broadly supported yet—neither Adobe Photoshop nor Lightroom Classic 2021 open the files. Sony offers software to convert the HIF files to your choice of TIF or JPG, but we recommend you stick with Raw capture if your workflow involves post-processing.
The camera applies noise reduction to JPG and HIF output, but even at ISOs considered extreme for other cameras, images hold up here. You'll enjoy nearly perfect detail and no visible noise through ISO 6400. There's a slight softening at ISO 12800, and blur sets in noticeably at ISO 25600 and 51200, the highest sensitivities where JPG noise is measured under 1.5%. There's some more noise and blur increasing through the top ISO 409600.
It's best to use Raw capture if you need to push the camera to its very extreme high ISO range. Noise is large and chunky at ISO 409600, a bridge too far even for this sensor. But Raw photos at ISO 204800 are surprisingly good—still very grainy, but detail shines through and color holds up.
At ISO 102400 and below, you'll net photos with smaller bits of noise, similar to fine grain film stocks. By the time you've dropped down to ISO 6400, the output shows very little noise and exquisite detail.
Robust Video Toolkit
The a7S III offers as much in the way of some of Sony's cinema cameras—it's just about the equal of the compact FX3 in function.
When cropped to the 16:9 video ratio, the 12MP sensor captures 4K video at native quality, without any sort of binning, line skipping, or downsampling. Autofocus is as capable as with stills (when using a native lens) and the pixel readout is quicker than the a7S II so the camera records slower slow motion and does a good job avoiding rolling shutter distortion. That's good news for handheld work, panning shots, and fast-moving subjects.
There's a downside: The camera doesn't support 6K or 8K capture, simply because it doesn't have enough pixels to manage. The Panasonic S1H is a similar hybrid model with 6K support, and worth a look if you're working on projects that require more than 4K.
But as a 4K camera, the a7S III delivers. It supports XAVC HS 4K, XAVC S 4K, and XAVC S-I 4K recording formats. You'll get the best quality and reasonable file sizes with XAVC HS 4K at your choice of 50 or 100Mbps, but the video does require some computing horsepower to edit. XAVC S-I 4K takes up more hard drive space (240Mbps), but doesn't compromise on quality.
If your system isn't quite up to the HEVC format used by XAVC HS, and you don't want to deal with larger file sizes, you can opt for XAVC S. File sizes are similar to the HS variety, but the compression isn't quite as advanced. Still, every mode supports 4:2:2 10-bit video internally. You can also opt for 1080p capture in XAVC S HD or XAVC S-I HD, useful if you don't need extra pixels and want to take advantage of smaller files and a Super35mm crop option.
Off-speed recoding is supported, too. The S&Q position on the mode dial is there for slow and fast motion, with a variety of recording and playback speeds. The camera can record fast-motion footage (1, 2, 4, 8, or 15fps), or push to 60 or 120fps for a slow-motion effect. For the clip above, I went with 120fps capture and 24fps playback, a five-times slow-down effect. Just as with standard motion, S&Q supports 4:2:2 10-bit recording internally, though you'll need a CFExpress Type A card.
The a7S III includes the expected Vivid, Black-and-White, Neutral, and other Creative Looks—they work for both photos and videos and net footage that's ready to share without color correction. Videographers will prefer Sony's Picture Profiles, a set of creative looks that work for stills too. There's no confusing the two—you can't use a Creative Look if you've got Picture Profiles turned on, and vice versa.
I recorded our test footage with Sony's S-Cinetone profile, assigned to Picture Profile 11 by default. It's delivers pleasing colors with a bit of desaturation—and no need to grade. If you prefer to apply your own look, S-Log2 and S-Log3 are both available as flat profiles. For ready-to-share HDR, the HLG profile is included.
A Video-First Hybrid Camera
The Sony a7S III is the only current-generation mirrorless camera with a relatively low pixel count sensor, especially appealing for 4K video and low-light photography. It's also one of the few that's a true hybrid—it's just at home in the hands of a photographer as it is with a trained cinematographer.
A brilliant eye-level viewfinder, fast continuous drive, and reliable tracking focus, as well as a mechanical shutter for sync with off-camera flashes, are just a few of the highlights here for photography, and reasons to choose the a7S III over dedicated cinema cameras like the FX3.
And as a video camera, the a7S III is just as capable of its cinema-line sibling. It uses the same sensor and video engine as the FX3, so you get the same 10-bit video and S-Log, HDR HLG, and S-Cinetone profiles. It's small enough to use on a gimbal, and there are no shortage of lenses available. The Sony system has one of the largest native libraries, and the a7S III can mount Arri PL lenses via an adapter.
Hybrid creators with more of an eye for video will be well served by the a7S III. Its 12MP BSI sensor offers cleaner high-ISO imaging and video than more typical 24MP cameras. And the ability to record in 4K at up to 120fps can add slow motion to projects without having to drop back to HD resolution.
It's more of a niche camera than entry-level crowd-pleasers like the Panasonic S5 and Sony a7 III, both Editors' Choice winners in the $2,000 range. That's been true of the a7S series since the first iteration, so if you're in its niche, be happy to know it's a marked update over the a7S II.
There are some other models to consider. We've not yet tested the Panasonic S1H, but it uses a different lens system, L-mount, records in 6K, and is one of the few hybrid models with an active cooling system. The Sony FX3 is also a contender, as its video toolkit is just as good, and cinematographers looking to build out a rig will appreciate its form factor.
The Sony a7S III has one of the best 4K video feature sets you'll find in a full-frame mirrorless camera, including 120fps capture for slow-motion playback.
Like What You're Reading?
Sign up for Lab Report to get the latest reviews and top product advice delivered right to your inbox.
This newsletter may contain advertising, deals, or affiliate links. Subscribing to a newsletter indicates your consent to our Terms of Use and Privacy Policy. You may unsubscribe from the newsletters at any time.
Thanks for signing up!
Your subscription has been confirmed. Keep an eye on your inbox!
Sign up for other newsletters
)