The Sony Alpha A7S Mark III is Sony's new "low-light" full-frame mirrorless camera, with a 12mp sensor, it should offer impressive noise performance for both stills photography, and 4K video recording. Videographers are going to be particularly interested in this camera as it features 4K video at 120fps, FullHD at 240fps, as well as in-body image stabilisation.
Sony Alpha A7S III Features
The Sony Alpha A7S III is designed to be the "ultimate" low-light camera from Sony. At the core of the Sony Alpha A7S III lies a full-frame 12mp BSI CMOS sensor, so not only does the camera benefit from larger pixels (with 8.4micron pixels, making it more sensitive to light), but it also benefits from a Back Side Illuminated sensor, further improving sensitivity to light. The sensor also benefits from faster (doubled) readout speeds, to reduce rolling shutter. To process the data from the sensor, there is a new BIONZ XR image processor which has been developed to give up to 8x more processing power (compared to the BIONZ X).
You've also got 5-axis in-body image stabilisation, that moves the sensor to help with slower shutter speeds as well as helping you get more stable video footage. Dynamic range is said to be an impressive 15-stops. There's also Active Mode for hand-held shooting to give improved stabilisation. ISO40 to ISO409600 is available giving a wide ISO range, and allowing for faster shutter speeds when needed.
You can record 4K UHD video at 120/100fps as 4:2:2 10bit ALL-I. You can use bitrates up to 600Mbps, and the camera uses HEVC/H.265 or AVC/H.264 encoding. There's S-Log3 gamma, S-Gamut3.Cine gamut available to give a wider dynamic range, as well as HLG (Hybrid Log-Gamma), to simplify HDR video creation. 16-bit RAW HDMI output is available to connect the camera to an external recorder, using the full-size HDMI port. There's also support for HD proxies for quicker workflow.
A graphite heatsink is built into the image stabilisation unit, which moves heat 5x more effectively allowed extended recording times, without worry about the camera overheating.
Focus is built-in to the sensor, with focal-plane phase-detection AF, with 759 focus points available, which of course, work both in stills and video recording. Focus also includes face and eye detection focus with tracking, which works for both humans, as well as animals, with the option to switch between the two in the menus. Eye AF is said to be improved, and you can use touch tracking to select the subject you want to track on the screen.
AF can be adjusted in a number of ways, letting you adjust the transition speed (7 levels), there's also AF Subject Shift Sensitivity (5 levels), and there's touch AF which can be used during manual focus operation. AF is sensitive down to -6 EV.
The camera will shoot at 10fps with AF/AE and will allow over 1000 shots as uncompressed RAW. There's also support for HEIF format images and HLG image capture modes. HEIF gives 10-bit colour, with better image quality and improved compression compared to JPEG.
Updates to the A7S III over the A7S II:
- New menu system!
- In-Body Image Stabilisation, up to 5.5 stops (vs 4.5)
- 9.4million dot electronic viewfinder, 0.90x magnification
- 3.0inch vari-angle touchscreen, with 1,440K dots
- New, FF 12mp BSI CMOS sensor
- 4K 120fps video recording (up to 30min)
- 4K 60fps (up to 60min)
- FullHD video at 240fps
- 10fps continuous shooting (vs 5fps)
- New, lower ISO speeds available (down to ISO40, vs ISO50)
- CFexpress Type-A support (dual slots)
- USB Type-C with PD support
- New Z battery support, up to 600 shots
- Bluetooth added
The camera has P, A, S, M shooting modes, giving you manual controls, plus 3 custom modes, Auto, and two different video modes on the mode dial. The two video modes are standard and S&Q (Slow and Quick).
There's also a 9.44 million dot electronic viewfinder (EVF) the highest resolution we've seen on any camera!
On the back, there's a 3.0inch vari-angle touch-screen, with 1.44m dots, and this can be tilted around to face forwards, which will be of particular interest for vloggers and other videographers. There's also a 9.44 million dot electronic viewfinder (EVF) the highest resolution we've seen on any camera, with 0.90x magnification, and dioptre adjustment. You'll find an Eye-detection sensor so the camera will automatically switch between the rear screen and EVF.
Connections and slots on the camera include dual side memory card slots, letting you use 2x CFexpress Type A or you can use SDXC UHS-II cards. The camera also has Wi-Fi 2.4GHz / 5GHz built-in, which is selectable depending on what you want to use. You'll also find NFC for quicker connections to compatible smartphones, and built-in low-power Bluetooth lets you transfer images using less battery than Wi-Fi, albeit with a slower transfer rate.
Key Features
- 12.1mp full-frame BSI CMOS sensor
- In-Body Image Stabilisation
- Up to 15+ stop dynamic range
- 9.44m dot QXGA OLED Tru-Finder EVF, 0.90x magnification (size can be reduced if too large)
- ISO40 to ISO409600
- 4K 120p recording, 10-bit, 4:2:2
- All intra up to 600Mbps
- FullHD 240p
- New S-Gamut3.Cine
- Fast hybrid AF in all recording situations
- Real-time eye AF (in video as well), Touch-tracking
- 759 phase-detection AF points 92% coverage
- 425 CDAF points
- 10fps continuous shooting with AF/AE
- Articulated vari-angle touch-screen
- Dual slots: SD UHS-II / CFexpress Type A card support
- Z battery
Sony Alpha A7S III Handling
Handling - As new versions of the Sony Alpha series have been introduced, they've grown in size, however, they still remain relatively compact, and if you have large hands, you may find that your little finger can slip off the bottom of the camera. If this affects you, you might want to look at an optional battery grip. The larger size has enabled a larger grip, as well as Sony's larger battery, for improved battery life. The grip is of a good size (other than somewhere to support your little finger), and there is ample rubber coating.
The movie button has been moved following feedback from users, to make it easier to use.
The camera has a solid build quality and has weather-sealing to make it suitable for use in inclement weather. The edges on the camera are mostly hard-edged, without the smoothing you find on Canon cameras. The camera feels good in the hand, once you get used to some of the harder edges, and thankfully the bottom of the camera and the areas in contact with your right hand are more rounded.
The layout of buttons and controls are quite neatly laid out, and won't take too long to get used to. The mode dial has a locking button on top, which you need to press in so that you can turn the mode dial. This can be a little "fiddly" at times, as it doesn't let you leave it unlocked. There are 3 user modes on the mode dial. The exposure compensation dial can be locked and unlocked, by simply pressing the button in the middle of the EV compensation dial. There are four Custom buttons, labelled as C1, C2, C3, and C4.
On the back, there's the usual joystick control making it easy to adjust settings, and this has a grippy texture making it easy to use. It's also a good size compared to some other cameras. The touch-screen interface is greatly improved and can be used to select and set menu options.
Auto-focus - There are 759 AF points covering a wide area of the frame. AF is sensitive down to -6EV, and up to 20EV, which gives a great range and can help in very dark situations. Focus options include face and eye detection, and you can choose between humans and animals. Auto-focus is quick and rapid and works well in both stills and video.
The electronic viewfinder (EVF) has an ultra-high-resolution of 9.44million dots. This makes the view extremely clear, extremely crisp, and detailed. For photography, this is great, with a 0.90x magnification the view is large and easy to see. The EVF has a refresh rate of 50/60fps (Standard PAL/NTSC), or 100/120fps (High PAL/NTSC). For video users, I'm not convinced they will see the benefits of the EVF, and perhaps they would prefer a larger screen with a higher resolution.
The 3.0inch vari-angle screen is the first one to be found in a Sony Alpha camera, with only one other Sony camera (currently) featuring a vari-angle screen, the Sony Z-V1. The screen has a resolution of 1.44m dots, which doesn't match other high-end mirrorless cameras. However, the screen still looks good, with good colour reproduction, and as you can adjust the angle of the screen it's possible to position it for the best view. It's also suitable for videographers, and vloggers, being possible to turn the screen to face forwards.
The Sony Alpha A7S III introduced a new menu system, with a new layout, that is designed to make it easier to find options and settings. Each section is colour coded, and you can also use the touch-screen to scroll through, select and change options and settings. When you switch between photo and video modes, the menus options are updated to give you the right set of options, so in video mode, you get video menus. At the top of the menu system is the "MyMenu" section where you can add your favourite (or most accessed) settings. You can see the different options in the video below.
The side memory card ports support either SD cards, or CFexpress Type A card. If you do want to use CFexpress Type A cards, it's worth being aware of the price of the cards, £210 for 80GB, £400 for 160GB, and the reader itself is priced at £140.
Tough G CFexpress Type A Card and Reader
Battery life - Battery life is rated for up to 600 shots using the LCD screen and 510 using the EVF (according to Sony / CIPA test results). This gives great performance for stills photographers, and for videographers, you can record 80 minutes (EVF), or 95 minutes (LCD). Continuous recording is 130m (EVF), 135m (LCD). You can also power the camera with an external power bank compatible with USB PD.
Sony Alpha A7S III Performance
The performance section is where we look at the image quality performance of the camera. Additional sample photos and product shots are available in the Equipment Database, where you can add your own review, photos and product ratings.
Sony Alpha A7S III Sample Photos
Sample Photos - JPEG images produced by the camera come out very sharp, possibly over-sharpened (depending on your personal preferences and the subject you're shooting). However the "Creative Look" can be adjusted to alter this and other settings, with options for contrast, highlights, shadows, fade, saturation, sharpness, sharpness range, and clarity. Colour reproduction is good, and like sharpness, can be adjusted.
Face and eye-detection work extremely well for both people and animals, and you can specify whether you're photographing Humans or Animals in the menus. Auto-detection would be nice.
Focus works well in low-light conditions, although your mileage may vary, depending on how dark it is, and of course the subject being photographed. In normal lighting conditions focus is very rapid, and very reliable.
Exposure and metering are reliable, with the camera delivering consistent results time after time. The dynamic range captured by the camera is good, with the "Dynamic Range Optimisation" option giving an improved dynamic range in JPEG images. You can use the HDR shooting mode if you want further dynamic range to be captured.
Lens correction options are built-in to the camera, including shading compensation (vignetting), chromatic aberration compensation, and distortion compensation.
The camera supports HEIF file format, which is 10-bit, compared to JPEG's 8-bit colour range. However, there's limited support for HEIF files (on PCs, with packages like Adobe Photoshop not supporting HEIF yet), and you can't convert HEIF images to JPEG in the camera.
12mp may seem like not enough for many people however, it's the lower pixel count and larger pixel size that gives benefits in low-light and dynamic range.
Sony Alpha A7S III ISO test images
ISO Noise Performance - Noise is very low from ISO40 all the way up to ISO1600. At ISO3200 noise is still low, but very fine detail is reduced slightly. At ISO6400 noise is still low, but there is another reduction in very fine detail. At ISO12800 noise becomes more noticeable, and fine detail drops. Detail drops again at ISO25600 as noise increases. However, the level of detail can still be considered relatively impressive, giving slightly better results than the 20mp FF sensor found in the Canon EOS-1D X Mark III. As well as detail being reduced at ISO51200, colour saturation also drops. Noise is strong at ISO speeds above ISO51200. ISO409600 is best avoided entirely. These shots were taken on the default settings for noise reduction.
Sony Alpha A7S III White-balance test images
White Balance Performance - Auto White Balance (AWB) options include "Standard", "Ambience" and "White" letting you set your preference, depending on your subject and what you want the camera to do. This means you can get warm results (for flattering portraits for example), or whiter results for product shots (as an example). Using the tungsten preset under tungsten lighting gives a corrected image. AWB performs well in mixed light, and under fluorescent light. There are a number of different fluorescent presets so you can find one that matches the type of fluorescent lighting you're using.
Sony Alpha A7S III Digital filters
Digital Filters - Creative Look replaces "Creative Style" and is shown above, these include options for contrast, highlights, shadows, fade, saturation, sharpness, sharpness range, and clarity.
Video - High-speed 4K UHD video at 120fps looks excellent! The camera uses the full pixel readout, with no pixel binning, with no crop when recording 4K 60p, and the camera can record 4:2:2 10-bit internally. Video quality is impressive, with clear, sharp, detailed footage. High-speed FullHD video at 240fps requires better lighting, or there is a drop in video quality.
Picture profiles are where you'll find all of the video profiles, with options for Black level, Gamma, Black Gamma, Knee, Color Mode, Saturation, Colour Phase, and Colour Depth. You can also copy picture profiles. You can also use the Creative Look(s) to adjust settings.
You can switch between NTSC and PAL mode in order to switch between 120/100fps and other frame rates, and the camera no longer asks you to format the memory card! Something that is very welcome.
ISO80 to ISO409600 is available for video recording. Videographers may be interested in reports of a "Dual ISO" feature built-in to the camera, which is automatically applied when you get to a certain ISO speed, and we'd recommend having a look at Philip Bloom's video on A7S III Dual ISO.
Image stabilisation does an excellent job of producing stable footage, even when handholding the camera with no additional support. An active mode is available for when you might need additional stabilisation, for example when vlogging.
If you're looking for a camera to record 4K video at 120fps, then the A7S III is unlikely to disappoint, thanks to a vast array of options and features available, as well as a well thought out design that minimises and avoids any overheating issues when recording for long periods of time.
You can view additional videos recorded with the A7S III on the ePHOTOzine YouTube Channel.
Value For Money
The Sony Alpha A7S Mark III is available for £3799, this makes it quite expensive compared to other cameras, however, it's less than the Canon EOS R5, the only other camera capable of recording 4K 120fps video. It's also offering the most compelling option for low-light use.
Canon EOS R5, 45mp, 8K 30p, 4K 120/60p video recording, £4199 body only
Canon EOS R6, 20mp, 4K UHD 60fps, FullHD 120fps video recording, £2499 body only
Panasonic Lumix S1H, 24mp, 6K 24p, C-4K 60fps, FullHD 180fps video recording, £3598 body only
Leica SL2, 47mp sensor, 5K video, C-4K 60fps, FullHD 180fps video recording, £5300 body only
Nikon Z7, 45.7mp sensor, 4K UHD 30fps video, FullHD 120fps, £2699 body only
Have a look at more options in the Top 25 Best Premium Mirrorless (with EVF), and the Top X Best Full-Frame Mirrorless Cameras. You'll also need to buy a memory card and a case or bag to keep your camera safe and protected - have a look at our complete guide to camera bags.
Sony Alpha A7S III Verdict
If we cut to the chase, the Sony Alpha A7S III is, ultimately, designed for videographers. In this area, the A7S III excels, giving video capabilities beyond what most other mirrorless cameras offer. With the exception of the Canon EOS R5. However, the A7S III does not suffer from the same overheating issues as the R5, and if you don't need or want 8K video, then the A7S III is going to be a better choice. It also offers exceptional low-light performance, with a 12mp BSI CMOS sensor. 4K footage recorded at 120fps looks excellent, and the in-body image stabilisation does an excellent job keeping video steady.
You've got a 3inch vari-angle touch-screen, which should keep vloggers happy, although it would be nice if the size and resolution were improved. We're impressed by the new menu system, which can be used with the touch-screen, and being able to switch between NTSC and PAL without formatting the memory card is finally resolved!
For stills photographers, the 12mp resolution is likely to feel limiting, especially when we're used to using 20/24/36/45mp cameras. It's a shame, as the 9.44m dot EVF is excellent, and will make any viewfinder user happy with the view. However, for those that need to shoot in very low-light conditions, then the A7S III may be an option. You've also got the new Z battery, that gives 600 shots, as well as a weather-sealed camera body, that should make it suitable for use in a variety of conditions.
For videographers who want high-quality 4K video, the A7S III has got to be extremely desirable. Especially as 4K video is far easier to deal with compared to 8K footage, and can be recorded to SD cards. For stills photographers, then you've got to be shooting in really dark conditions for the A7S III to be needed.
| The Sony Alpha A7S III is an exceptional video camera, with excellent low-light performance, however, it may not have enough resolution for stills photographers. |
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