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Key takeaways
- Redesigned menus with touchscreen operation
- Large, high resolution viewfinder
- Updated ergonomics from a9 II and a7R IV
- Dual card slots that accept either SD or CFexpress Type A
EVF
The a7S III is the first camera to use a new 9.44M dot OLED EVF. That's 2048 x 1536 pixel resolution: 27% higher in each direction than the 5.77M dot finders found in the best of its peers and literally twice the resolution in each dimension of the panel used in the a7S II.
Despite its high resolution, it can be run at up to 120 frames per second, giving an impressively lifelike view on the world. However, in its default mode it isn't being driven at anything like its full resolution. Switching to 'Display Quality: High' boosts this but the preview still doesn't look quite as detailed as playback mode.
In addition to its impressive resolution, the viewfinder has magnification of 0.91x, which means it's very large. An eye-point of 25mm means you're likely to be able to see to the corners of the display even with glasses on but there's a 'zoom out' option that uses a smaller area of the screen if it's not sufficient.
Articulating screen
The a7S III also has a fully articulating rear LCD: a first for an a7-series camera. It's an oddly low resolution panel (1.44M dots) for a camera of this price, especially one in which the LCD is likely to be a primary means of interacting with the camera. But it's touch sensitive to a much greater extent than previous Sony cameras, which we'll cover further down the page.
'Fourth gen' ergonomics
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Although it's only the third a7S camera, the a7S III gets the much improved ergonomics introduced on the a7R IV. This means a more comfortable grip, large grippy joystick and prominent AF-On button. It also features the togglable lock on the exposure comp dial and the mode dial lock that needs to be pressed to turn the dial.
The camera also feels a little more responsive that previous Sonys we've used, making the connection between your button presses and the camera's response feel more direct.
SteadyShot Active
In addition to all its other video features, the a7S III becomes the first Sony mirrorless camera to offer the SteadyShot 'Active' mode. This applies a slight (1.13x) crop to the sensor, which allows the mechanical IS system to make larger movements without risking vignetting.
The 'Active' mode is specifically designed for situations in which you're moving with the camera: perhaps walking or on a vehicle with significant engine vibration.
Full-sized HDMI
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In keeping with the serious video focus, the a7S III joins the likes of Panasonic's S1H in offering a full-size HDMI connector. This is a much more durable connector that's much less likely to drop the signal if anything touches the cable.
The camera comes with a fairly sizable screw-in cable retainer that slots over the top of the port doors. This protects the head of the HDMI lead and also secures the cable so that any pull on the cable is at right-angles to the socket. The design leaves all the other sockets accessible but limits the degree to which the screen can be flipped out.
Revised menus
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One thing that you won't see on the spec sheets is that the a7S III has a totally re-designed menu system. Sony had already added better categorization and color coding to its menus before but this is a much more profound redesign.
To cope with the much more complex menus on a modern camera, the new menu system is based on a series of vertical tabs, which are then broken down into a series of sub-sections. It also shows the options within the current sub-section, so that you can see all the way down to individual options while retaining a clear picture of where you are in the overall structure.
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This is slightly undermined on 'Shooting' and 'Setup' tabs, where there are more than seven sub-sections, such that you can't make an 'at a glance' assessment of all the possible categories of options, but generally the redesign will demand much less memorizing of the menu structure than before.
The underlying groupings of menu options remains consistent with the existing cameras, so existing Sony users should find themselves able to adapt pretty quickly.
More extensive use of touchscreen
Another area Sony has regularly been criticized for (by others as well as us) is the under-utilization of their touchscreens. The a7S III puts this right by letting you control both the Fn menu and main menus using the touchscreen.
Unfortunately an existing bugbear of ours persists: the tap-to-track setting that's so useful for video persists into stills shooting (where it would be more useful to tap to set focus point). Still, at least it now defaults to tap-to-track, rather than you having to change a menu setting to activate subject tracking for video.
Dial customization
The a7S III is a three dial camera: front, rear shoulder, rear face with a dedicated exposure comp control, too. By default the front and rear top dials control aperture value and shutter speed (the order can be reversed). There's also an option to put exposure comp on one of the top dials for Aperture Priority and Shutter Priority modes, if you wish.
The dial on the rear face does nothing by default but can have one of 12 functions assigned to it via the 'Custom Key Setting' menus (in the 'Operation Customize' section of the menu, not 'Dial Customize').
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If you really have strong ideas about what each dial should do, you can create 'My Dials' presets. These lets you assign any of the 12 assignable functions to any of the dials and create up to three different My Dial modes.
You need to configure a custom button to access these My Dials modes. This can either give direct access one of the My Dial presets (toggling or just when the button is held), or can cycle between presets.
Dual dual-format card slots
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Sony has a long history of making card slots that could accommodate more than one media type, and the a7S III revives this tradition. However, rather than offering SD and Memory Stick compatibility, the Mark III becomes the first camera we've encountered to use the new CFexpress Type A format. Both slots can accommodate either UHS-II SD cards or CFexpress A cards.
CFexpress Type A are a new, smaller format introduced in V2.0 of the CFexpress standard. They use the same interface technology as the existing (XQD-like) CFexpress Type-B cards but with lower maximum read/write speeds. However, even though they're not as quick as Type-B cards can theoretically become, they're still quicker and offer larger maximum capacity than most UHS-II cards on the market (they're based on the same technology as SD Express, which is two generations beyond UHS-II).
Battery
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As with autofocus, the Mark III sees the a7S series finally gain the bigger battery introduced to the rest of the range back in 2017. The 16.4Wh NP-FZ100 battery is rated for 600 shots per charge using the rear screen and 510 using the EVF. As always, CIPA numbers are broadly comparable between cameras but most photographers will find they get twice as many shots as quoted. A 600 shot rating is enough that it's unlikely you'll ever need to think about battery capacity when you're shooting.
The USB-C port can also be used to charge or power the camera if used with USB PD compatible power sources. Note that it's a case of power or charge: the battery does not charge while the camera is being operated using USB power.
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