The Sony a7S III Arrives With Some Surprises

Key Features

• 12.1MP Exmor R image sensor 
• BIONZ XR processing engine 
• 9.4mm dot Viewfinder 
• Improved AF performance 
• Extensive Movie Assist functions 
• ISO range 80-102400, 40-409600 (Expanded)
• 15 stops of dynamic range 
• 4K full pixel readout without binning 
• 759 Phase Detection AF points, 92% area coverage

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Sony invested a lot in its Exmor R sensor, which dates back to 2008, and has stuck with it for the a7S III improving upon it further with larger photosites and a faster read out. Sony says the newly developed 12.1MP sensor has a 2x faster readout, and filmmakers will benefit from a sensor that provides a full pixel readout without binning.

What Sony has done is improve the back-illuminated sensor so that the a7S III has a better dynamic range while keeping a lower noise floor and low megapixel count. The combination of larger photosites and the back-illuminated sensor makes it more respective to light and is why Sony claims the camera has 15+ stops of dynamic range. 

The new BiONZ XR has 8x more processing power than the previous BIONZ X which will minimize latency and improve movie processing. The next-gen engine allows for faster AF/EF and Face/Eye Detection processing, better color reproduction, and high speed frame rates.

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Video Formats

Sony has continued on its path of refining what the Alpha series is known for and improved up on it with the a7S III. To start, the a7S III has a completely new menu structure. One that has independent options for stills and video, including settings for focus, exposure, picture profile, and white balance. The camera even allows you to white balance while recording a movie. 

Better yet, the a7S III allows for simultaneous display on the camera and to an external recorder, which an record 16-bit RAW. To what external monitor you might wonder? The Atomos Nina V of course. Since No Film School has learned that Convergent Design won't be pursing the Apple ProRes RAW, Atomos pretty much has a stranglehold on the format at the moment. 

Sony has kept with 4K UHD for the a7S III, but has stated if more people want 4K DCI, it's something that might be added in the future. Sony also included XASC S-I 4K ALL-I along with the familar XAVC HS 4K Long GOP and XAVC S 4K Long GOP codecs. All formats have an option for internal 10-bit 4:2:2 recording at various sample rates. Depending on the selected format, a SD card or CFexpress will be needed. As with previous Alpha cameras, there are Slow and Quick recording options as well. 

XAVC HS 4K Long GOP 
Normal 

• 24/60/120p, 10-bit 4:2:2, 280Mbps
• 24/60/120p, 10-bit 4:2:0, 200Mbps

S&Q 

• 1/2/4/8/15/30/60/120p at 24p 10-bit 4:2:2, 100Mbps
• 1/2/4/8/15/30/60/120p 10-bit 4:2:0, 100Mbps

XAVC S 4K Long GOP 
Normal

• 24/60/120p, 10-bit 4:2:2, 280Mbps
• 24/60/120p, 8-bit 4:2:2, 200Mbps

S&Q

• 1/2/4/8/15/30/60/120p at 24p, 10-bit 4:2:2, 100Mbps
• 1/2/4/8/15/30/60/120p, 8-bit 4:2:0, 100Mbps

XASC S-I 4K ALL-I
Normal

• 24/30/60p, 10-bit 4:2:2, 600Mbps

S&Q

• 1/2/4/8/15/30/60/120p at 24p, 10-bit 4:2:2, 240Mbps

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IBIS / Autofocus 

The 5-axis optical in-body stabilization provides up to 5.5 steps of compensation. Like previous models, the IBIS on the a7s III has a slight crops when active. The autofocus on the a7S III has improved as well – about a 30% improvement from the previous BIONZ X processor. The Fast Hybrid AF combines Phase and Contrast AF to include 759 Phase AF and 425 Contrast points that cover 92% of the sensor.

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Body

The a7S III keeps the familiar small form factor of its full-frame predecessors which many Sony shooters will enjoy. One big addition is an articulating touchscreen. Sony also developed a 9.44 million-dot QXGA EVF for the a7S III which is an enormous amount of dots. Compared to the Canon EOS R5 at 5.76 million and the Sony a7 III at 2.3 million dots. The EVF has a 0.9x magnification and a 41° field of view with a 25mm high eye point. 

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Power / Storage

The a7S III sees a brand new battery that offers up 60% longer run times than the a7S II. Sony suggests users will see 95 minutes of record time compared to 60 minutes using the older batteries.

The camera also receives a new storage type in CFexpress Type A cards which allow you to record 4K 60p. Featuring dual card slots, both slots can fit either a SD or CFexpress Type A card. Meaning, there are still only two slots on the camera. The SD pins go to the left, the CFexpress pins go to the right. Sony is offering capacities of 80 GB and 160 GB in its Tough memory card brand, along with a new memory card reader. 

Price & Availability 

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The Sony a7S III is available for pre-order now for around $3500 depending on your country of origin. It's expected to ship by September.