Sony a7SIII Announced: Full-Frame 4K/120fps and Unlimited 10bit Video!

Shipping in September, the a7s III may just be worth the 5 year wait!

sony a7S III
Images by Sony

The day is finally here. The ‘unicorn’ has landed, but will it exceed our expectations as Sony promised? Read on to find out all you need to know about the new Sony a7SIII.

After nearly 5 years of promises, Sony officially unveiled the α7s III earlier today in a low-key, straight to the point live stream presentation.

The third ‘S’ model comes loaded with some spectacular 4K video features such as full-frame video up to 4K/120fps, 10bit 4:2:2 internal recording including 4K/60p, ’16bit raw output’ via HDMI, a flip-out screen, a full size HDMI, improved AF and IBIS, and much more. 

New 12MP Full-Frame Sensor with Big Pixels

Every since the first alpha 7S back in 2014, the ‘S’ models have been the de-facto video-first, stills-second cameras in the Sony mirrorless world. And since bigger pixels and a lower total pixel count make the math a lot easier for the processor, it makes perfect sense for Sony to keep the total megapixel count to the same 12MP as the previous generations. 

However, the Sony a7sIII has a newly designed 12.1 megapixel full-frame, back-illuminated CMOS sensor with a much faster readout compared the previous generation model. Furthermore, Sony coupled the new sensor with a new BIONZ XR processor, which significantly reduces rolling shutter. This was a huge problem on the a7s and a7s II. 

According to Sony, they rate the sensor at 15+ stops dynamic range when shooting in S-log3. Naturally, the a7s III is a low-light monster, with maximum ISO of 409,600 and usable ISO values in the 20,000s. Coupled with the new 10bit 4:2:2 codec, this camera is shaping up as an incredible documentary tool. 

Sony a7s III full frame 12mp sensor bsi exmor
Images by Sony

Super-fast Phase Detect Autofocus

A first in the S-series, the a7s III features an the impressive Fast Hybrid AF with 759 phase-detection AF points covering 92% of the image sensor. And as such it makes it possible for the camera to track subjects over a wide area at high speed, precision and smoothness.

Moreover, Real-time Tracking and Real-time Eye AF are also present to help you not just nail focus, but also keep it while the subject is moving. According to Sony, their ‘advanced Real-time Eye AF improves detection performance by 30% over the previous system, thanks to the new image processing engine.’

It ensures accurate, reliable detection even when the subject’s face looks away. Real-time Tracking is initiated simply by touching the subject on the screen. Real-time Eye AF is automatically initiated when an eye is detected.

5-Axis Optical Image Stabilization, Re-Designed Menus, and a Flip-Out Screen

Yes, Sony finally did it – the a7s III is the first a7 camera to feature a front-facing screen. This feature alone is something I personally thought they’d never do, but they listed to us and did it. A collective slow clap for Sony here. 

Also, the new IBIS system has a new features called Active mode, which uses a 10% crop of the image to give you even smoother footage. 

And of course, speaking of the dreadful Sony menus, looks like Sony weren’t messing around when they said – everything is new. The Menu System is also redesigned for a more streamlined and less-confusing approach. From the promo videos it doesn’t appear to be VENICE or ALEXA calibre, not that anyone in their right mind would expect that, but hey it is a welcomed improvement. 

sony a7siii full size hdmi
images by Sony

4K/60p 16bit RAW output to Atomos via HDMI

Yes this is a full-size HDMI type A output on the side of the camera! This is a major improvement over any other Sony mirrorless camera. It may not be as sturdy and secure as a BNC, but on a camera of this class, it’s the best we’ll ever get.

And what’s even crazier is that the a7sIII will output a 16bit linear RAW signal up to 4K/60p to an external recorder. Atomos have already announced support with an upcoming firmware for their Ninja V.

Furthemore, the Atomos Ninja V will encode the signal as 12bit Log in ProRes RAW giving you even more flexibility in post. 

4K Video Features, Frame Rates, Codecs, CFExpress A Cards

The Sony a7s III can record up to 4K/120fps in 10bit 4:2:2, and also up to 240fps in Full HD, Sony is also debuting a new XAVC-S I (Intra) 10bit 4:2:2 codec in the a7s III, in addition to a more compressed XAVC-S HS codec based on the H.265 compression. The latter is supposed to give you smaller file sizes, but they will put more strain on your CPU in the edit.  

More interestingly, all frame rates and resolutions are available in full-frame, withouth a crop *except when you use Active Mode on the IBIS, which gives you a slight 10% crop. But that’s no biggie. 

Another huge feature is that supposedly the camera can run for extended periods without overheating in any resolution or frame rate! And there is no recording limit, which is bonkers. 

Of course, Sony do say that in 4K/60p you are limited to 1 hour recording (30 minutes in 4K/120fps as you’ll run out of cards), but that’s because you’ll run out of media and battery.

And speaking of media, the a7s III also makes use some brand new cards – CFexpress Type A, which are required for the highest bit rates and frame rates in 10bit 422 in 4K, such as 120fps.

Sony will be releasing two capacities CFexpress Type A cards at launch in September – an 80GB and a 160GB capacity model. 

Sony a7s iii cfexpress card a
Images by Sony

Unique Cooling System – No Overheating? 

Sony engineers have really thought this through – give the camera just enough megapixels to make great 4K images and cool the sensor/processor efficiently.

The new a7s III features a unique and effective fan-less cooling system designed to enable the camera to record continuously for extended periods of time.

Easier Matching to Sony FX9, VENICE and other Sony Cameras

Thanks to the new 10bit Intra codecs you can now get substantially less banding and artifacts in your S-log2 and S-log3 footage when graded. 

As expected, the three pro color gamma settings including S-Gamut, S-Gamut3, and S-Gamut3.Cine are present, allowing you to easily match a7s III footage shot to bigger cameras like the FX9 and even VENICE. Sadly, S-Cinetone is not present, however Sony claim that due to the new processing, improved image quality and 10bit codec, the a7s III footage should be a breeze to match to higher-end Sony cameras.

Furthemore, HLG (Hybrid Log-Gamma) picture profile familiar to Sony a7 III users is also here as well. 

Full Sony α7s III presentation below:

The new card slot design accommodates both the new CFexpress A cards and the SDXC UHS-II cards (not at the same time). This is a neat design feature, which enables you to use your existing SDXC cards for the less intensive resolutions and frame rates. 

Pricing and Availability

The a7S III is priced at $3,499.99 USD and $4,800 CAD. UK dealers are currently taking pre-orders at £3799 inc. VAT. 

If you are in North America you can pre-order from B&H, and other authorised dealers. For more info head over to Sony here.

I must admit, after waiting for so long many Sony users lost hope that Sony will ever bring an updated a7s model, but I am glad they took their time. I have not tested or seen the camera, but from what I’m seeing in first look videos, it looks like Sony really though this camera through – a solid 4K workhorse in a familiar compact form, free of overheating issues. The last remains to be tested in the field after release, but it looks very promising. 

It is reasonably priced given its impressive features, and I am sure it will be very popular with a lot of creative folks. 

What do you think?

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