Sony Adds 4K to New a7 III Mirrorless Camera

Here's everything we know about the new Sony a7 III mirrorless camera. 

Its a7 II predecessor packed a 24.3MP Full-Frame Exmor CMOS sensor capable of shooting full HD at 24, 30, 60 fps (50 Mb/s) for roughly $1,100. The latest edition can record internal 4K video, but is it everything you want in a camera with a small footprint. In a live streaming event, Sony shared its latest offering, the full frame a7 III mirrorless camera – which was mistakenly introduced as the "a9 III" by Kenji Tanaka of Sony. 

Features at a glance:

  • 24.2MP Back-Illuminated Exmor R CMOS Image Sensor 
  •  ISO range of 100 - 51200 (expandable to ISO 50 – 204800 for still images) 
  • 15-Stop dynamic range at low sensitivities
  • AF system featuring 693 phase-detection AF points covering 93% of image area, 425 contrast AF points and fast
  • Improved Eye AF
  • 10 fps continuous shooting with either mechanical shutter or silent shooting and full Auto Focus/Auto Exposure tracking
  • 5-axis optical in-body image stabilization with a 5.0 step shutter speed advantage
  • High-Resolution 4K  shooting with full pixel readout and no pixel binning across full-width of full-frame sensor
  • 710 shots per charge with NP-FZ100 battery
  • Joystick, Dual SD Card Slots, SuperSpeed USB Type-C 3.1
  • Available in April for about $2000 US 

Image Quality

A 24.2MP back-illuminated Exmor R CMOS image sensor is paired with a front-end LSI that effectively doubles the readout speed of the image sensor. An updated BIONZ X processing-engine boosts processing speed by approximately 1.8x compared to the a7 II. The ISO range of 100 - 51200 (expandable to ISO 50 – 204800 for still images) is an overall 1.5-stop improvement in image quality. The camera also features 15-stop dynamic range at low sensitivity settings.

The camera can also output 14-bit RAW format even in silent and continuous shooting modes, and carries the familiar 5-axis optical image stabilization system that results in a 5.0 step shutter speed advantage.

AF Speed and Performance

The a7 III features 4D FOCUS capabilities using 425 contrast AF points that work with a 693-point focal-plane phase-detection AF system found on the a9. AF response and tracking have also been improved with almost 2x the focusing speed in low-light condition and 2x the tracking speed compared to the previous model. An improved Eye AF feature is also available, even in AF-C mode. 


The updated image processor allows it to shoot full-resolution images at up to 10 fps with continuous, accurate AF/AE tracking for up to 177 Standard JPEG images, 89 compressed RAW images or 40 uncompressed RAW images. This high-speed mode is available with either a mechanical shutter or a completely silent shooting. The camera can also shoot continuously at up to 8 fps in live view mode with minimal lag in the viewfinder or LCD screen.

Additionally, if there is fluorescent or artificial lighting present in a shooting environment, users can activate the Anti-flicker function to allow the α7 III to automatically detect the frequency of the lighting and time the shutter to minimize its effect on images being captured. 

4K Video

The  a7 III offers 4K (3840x2160 pixels) video recording across the full width of the full-frame image sensor. In video mode, the camera uses full pixel readout without pixel binning to collect about 2.4x the amount of data required for 4K movies and then oversamples it to produce the 4K footage. 

An HLG (Hybrid Log-Gamma) picture profile is available on the a7 III, which supports an Instant HDR workflow, allowing HDR (HLG) compatible TVs to playback 4K HDR images. Both S-Log2 and S-Log3 are available for increased color grading flexibility, as well as Zebra functionality, Gamma Display assist and proxy recording. The camera can record full HD at 120 fps at up to 100 Mbps, allowing footage to be reviewed and eventually edited into 4x or 5x slow-motion video files in full HD resolution with AF tracking.

Video clips can be up to 29 minutes long (NTSC/PAL) in the samples below: 

4K XAVC S via H.264

  • 3840 x 2160p at 23.98, 25, 29.97 fps (100 Mb/s )
  • 3840 x 2160p at 23.98, 25, 29.97 fps (60 Mb/s)

HD XAVC S via H.264

  • 1920 x 1080p at 100, 120 fps (100 Mb/s XAVC S)
  • 1920 x 1080p at 100, 120 fps (60 Mb/s)
  • 1920 x 1080p at 23.98, 25, 29.97, 50, 59.94 fps (50 Mb/s)
  • 1920 x 1080p at 50, 59.94 fps (25 Mb/s)
  • 1920 x 1080p at 25, 29.97 fps (16 Mb/s)

AVCHD via H.264

  • 1920 x 1080i at 50, 59.94 fps (24 Mb/s)
  • 1920 x 1080i at 50, 59.94 fps (17 Mb/s)

Build, Design and Customization

Sony added α9 functionality into the α7R III including dual media slots, with support in one slot for UHS-II type SD memory cards. Battery life has been extended with a CIPA measurement of up to 710 shots per charge on Sony’s Z series battery NP-FZ100. It offers approximately 2.2 times the capacity of the W series battery NP-FW50 on the α7 II.

Additionally, there is a total of 81 functions that are assignable to 11 custom buttons, and the camera is both dust and moisture resistant. The α7 III features a high-resolution, high-contrast, fast-start XGA OLED Tru-Finder with approximately 2.3 million dots. “Standard” or “High” display quality settings are also available for both the viewfinder and monitor. 

Below you can compare the specs between the a7 II and a7 III. 

Sony a7 III
Sony a7 III
Sony a7 III
Sony a7 III
Sony a7 III

a7 II Tech Specs

  • 35mm full frame (35.8 x 23.9 mm) Exmor CMOS sensor
  • BIONZ X image processor
  • 24.3 MP
  • AVCHD 2.0 / MP4 / XAVC S (up to 1920 x 1080/60p 50 Mbps)
  • ISO 50–25600
  • 5-axis image stabilization
  • Fast Hybrid AF system 
  • Phase-detection AF
  • Clean HDMI ouput
  • Sony E-Mount
  • Microphone / Headphone inputs

a7 III Tech Specs

  • 35 mm full frame (35.6 × 23.8 mm), Exmor R CMOS sensor with back-illuminated design
  • BIONZ X image processor
  • 24.2MP
  • 4K UHD recording 
  • S-Log2 and S-Log3
  • ISO 100-51200 (expandable to ISO 50-204800 for stills)
  • a9 AF 4D FOCUS (Fast Hybrid AF with 693 phase-detection and 425 contrast-detection AF points)
  • Eye AF
  • 5-axis image stabilization
  • Sony E Mount
  • Microphone / Headphone inputs

Pricing and Availability

Available in April for about $2000 US for the body and $2200 in a kit with the FE 28‑70 mm F3.5‑5.6 kit lens. In Canada, it will be sold for $2600 CA for the body and $2800 in a kit with the FE 28‑70 mm F3.5‑5.6 lens.     

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Your Comment


This is a fantastically good camera, I can't wait to try it. The only question is, what will the A7sIII have that this one doesn't already?

February 26, 2018 at 9:05PM

Noah Leon
Filmmaker @ Moosefuel Media

I'd assume the a7siii would have 10 bit and a 12mp sensor that has larger photosites for higher sensitivity. I am pretty tempted to pick this up more than an a7siii. I'd like to see what the max useable iso is. I rarely ever have to go up higher than 3200 which is like the minimum for the a7sii right?

February 26, 2018 at 9:19PM


February 27, 2018 at 6:45AM, Edited February 27, 6:45AM


Exactly, Panasonic gh line is getting overpriced lately. One should not remove the IBIS, put a sensor with less resolution (easier to make), increase the price and hope for better sales. The niche of gh line in a Sony ecosystem was a cheaper-price-world. That niche is over now. $1500 for a GH5s would be more realistic.

February 27, 2018 at 11:24AM, Edited February 27, 11:31AM


You still can't beat 10bit 4:2:2 4K 60p with VLog and Panny colors. GH5(s) still best bang for the buck when it comes to video IMO. I much prefer it over even the c200 8bit 4K 60p. Autofocus will probably be top notch but I'm traiding 10bit 4k 60p for autofocus.

February 27, 2018 at 12:08PM, Edited February 27, 12:10PM


But you have to use a recorder to get the 10bit 4k on the GH5(s) cams.

February 27, 2018 at 12:28PM


Neither are bad cameras. 4K 60fps vs full frame loveliness. The deal breaker for many people must be that a year or two down the line, will the market for what they create demand 60fps or not? Like many thought they would demand 3D for everything.

February 28, 2018 at 7:03AM

Julian Richards
Film Warlord

I think that some of the a7sIII predictions here are very wishful thinking. I think it's a very slim chance of it doing 10 bit, even to an external recorder. Since the a7sIII will be more "video focused," I'm betting the only advantages it'll have over this a7III is: 4k 60fps, maybe a HFR option like 240fps in 1080p, and of course it will be even cleaner in low light. I can't imagine it offering much more than that given their history.

February 28, 2018 at 9:09AM, Edited February 28, 9:09AM

Sean Kenney
Event Cinematographer

Having thought about this, with all my vintage full frame lenses, even though there are focal reducers for MFT, the A7iii is my lottery win camera. There's full frame video footage using a Sony and a 60's Helios lens on YouTube and it's amazing.

February 28, 2018 at 3:44PM

Julian Richards
Film Warlord