Sony A9 III boats world’s first full-frame global shutter CMOS sensor
Nov 7, 2023
Share:
Sony A9 III boats world’s first full-frame global shutter CMOS sensor
This is a camera that Sony shooters have wanted for a long time, but now it’s finally here. Sony has announced the new Sony Alpha A9 III (buy here). While its resolution stays relatively low, by today’s standards, its sensor features a global CMOS shutter.
Global shutters are something that camera users from all brands have wanted ever since cameras ditched CCD sensors. The Sony A9 III has beaten everybody to the punch on bringing global shutters back, but that’s not the only trick up its sleeve.
Sony A9 III – Global Shutter CMOS Sensor
The biggest news from a technical standpoint with the Sony A9 III is that it features a global shutter CMOS sensor. The idea of a global shutter is not new, but to see it in a video-capable mirrorless camera certainly is. Of course, it immediately made it to the top of our best Sony cameras guide.
Global shutter sensors have been around for a while. The CCD cameras used in the early days of DSLRs (my D100 and D200 bodies had them) were global shutter sensors. That means they’d capture the view from every individual pixel all at once.
Companies shifted from CCD to CMOS sensors because CMOS sensors were cheaper and easier to manufacturer and, for most consumer uses, kept up with CCD sensors just fine. At least for stills photography, when combined with the traditional mechanical shutter that SLRs had been using for decades.
The advent of video, however, brought forth the CMOS sensor’s one major flaw. Rolling shutter artifacts. Rolling shutter is what makes things lean when you shoot a photo from the side of a moving vehicle and airplane propellers bend and float in mid-air.
Global shutter sensors prevent such artifacts. The Sony A9 III represents the first interchangeable lens mirrorless camera to sport a global shutter CMOS sensor, but I expect it will start to become standard across at least new Sony models in the next couple of years, if not all manufacturers.
120fps continuous shooting for stills
With a camera that’s geared towards sports, wildlife and action subjects, high-speed continuous burst shooting is an important factor. The Sony A9 III pretty much just hammered everybody with the A9 III in this respect, though.
DSLRs hit 16-20fps at the highest end before they were usurped. Mirrorless cameras in recent times have been able to hit 30-60fps utilising the electronic shutter. The Sony A9 III ramps this all the way up to 120 frames per second.
But not only does it have the speed, it doesn’t have the sacrifices many other cameras have had to implement to reach those high speeds. The A9 III reaches 120fps while maintaining full real-time recognition autofocus and auto exposure, blackout-free on the EVF. And it’ll do it when shooting 14-bit RAW.
Its buffer fills up after 192 shots, giving you about a second and a half of shooting time per burst. But in most cases where you need to shoot this speed, you can anticipate and time things just right. And you can always drop it down a little to increase the overall duration if needed.
1/80,000th of a second with flash sync
Another area where the Sony A9 III has just pummelled the competition is with its maximum shutter speed. Most cameras that still contain mechanical shutter curtains are limited to 1/4000th or 1/8000th of a second. Many cameras bump this up to 1/16,000th of 1/32,000th with the electronic shutter.
The Sony A9 III lets you shoot up to 1/80,000th of a second, which is an insanely short amount of time. You’re going to need a lot of light for such shutter speeds, even at wide apertures, but if it supports flash sync all the way up to its maximum limit, that’s probably not going to much of an issue.
There is one slight caveat to that maximum shutter speed, though. When shooting continuous mode at the 120fps mentioned above, you’re limited to 1/16,000th of a second as your fastest exposure. This is still going to be plenty fast enough for most use cases, though. 1/80,000th of a second with continuous shooting mode is expected to come in a future firmware update.
Shoot before you’ve hit the shutter
The Sony A9 III also features pre-capture. This is a relatively new concept to cameras, but it essentially means that it’s shooting before you hit the shutter. How does that work?
Well, put simply, it’s just always shooting, whether your finger’s pressed down on the button or not. As its internal buffer fills up, older images are discarded to make room for new ones. Then, when you do hit the shutter, it can clear out the rest of its buffer to your memory card as needed.
It’s a bit more complex than that, but that’s a simple overview of the concept.
This is great for those who want to photograph events that are too quick to react to manually, like lightning strikes. Human reactions aren’t anywhere near fast enough to capture lightning. Typically they’re shot using long exposures in extreme dark, and then the shutter is closed after the strike.
Now, you’d just need to have your camera set up, ready to go, and as soon as you see the lightning strike and hit the button, the camera can grab it out of those pre-shot images for you. The pre-capture feature works at up to 120fps with timing settings of between 0.005s and 1 second.
4K 10-bit 4:2:2 internal with 16-bit raw over HDMI
Naturally, Sony hasn’t neglected the A9 III’s video features. It shoots downsampled 6K video at 4K internally. And it does it crop-free in 10-bit 4:2:2 using ALL-I encoding. It also exports 16-bit raw over HDMI to external recorders.
It features the usual S-Log3, S-Cinetone and other picture profiles. So, any video editing or colour grading workflows you’ve already established will continue to work with the new camera.
To save your footage and photos, it sports a pair of Sony’s dual-format CFexpress Type A and UHS-II SD card slots. So, no matter what format you’re shooting, you can insert memory cards that can keep up.
It has a USB-C port with USB 3.2 Gen 2 speeds for up to 10Gbps (1.25GB/sec) transfer speeds over a cable. On the back there’s a 3.2″ 2.1m-dot flippy out 4-axis touchscreen display and up top there’s a 9.44m-dot 0.90x OLED EVF refreshing at 240fps.
Overall, it’s a bit of a monster.
Sony A9 III Specs
Mount | Sony E |
Format | Full-Frame |
Sensor | Global Shutter Stacked CMOS |
Resolution | 6000×4000 (24-megapixel) |
Bit-depth | 14-Bit |
Electronic shutter | 1/80000 to 30 sec |
Continuous shooting | Up to 120fps 14-Bit RAW at full resolution |
Focus type | Auto & manual focus |
Focus modes | Continuous-servo AF (C), direct manual focus (DMF), manual focus (M), single-servo AF (S) |
AF points | Still images: Max. 759 points (phase-detection AF), Movies: Max. 627 points (phase-detection AF) |
AF sensitivity | -5 to +20 EV |
Stabilisation | 5-axis sensor-shift (up to 8 stops) |
Viewfinder | 1.6cm 9.44m-dot electronic viewfinder (240Hz refresh) |
LCD | 8cm 2.1m-dot 4-axis tilting touchscreen LCD |
Internal video | Up to 4K at 120fps 600Mbps, |
External video | 16-bit raw over HDMI |
Memory card slots | 2x dual format CFexpress Type A/UHS-II SD card slots |
Connectivity | Wi-Fi, Bluetooth, USB 3.2 Gen 2 |
Dimensions | 136.1 x 96.9 x 82.9mm |
Weight | 702g (with battery & memory card) |
Price and Availability
The Sony A9 III is available to pre-order now for $5,998 and is expected to start shipping in Spring 2024.
John Aldred
John Aldred is a photographer with over 20 years of experience in the portrait and commercial worlds. He is based in Scotland and has been an early adopter – and occasional beta tester – of almost every digital imaging technology in that time. As well as his creative visual work, John uses 3D printing, electronics and programming to create his own photography and filmmaking tools and consults for a number of brands across the industry.
Join the Discussion
DIYP Comment Policy
Be nice, be on-topic, no personal information or flames.