Those extra grams are well earned, too. The A7 III has a larger, more comfortable grip and a much bigger, 2,280mAh battery than the A7 II, which has a 1,020mAh cell. It's the same one used in the professional A9 and A7R III cameras, but the A7 III is less power-hungry. As a result, you get 700 shots per charge, the most of any mirrorless camera on the market. In practice, I could shoot for several hours and still have a 70 percent charge -- a major improvement over my A7S II.
Sony has finally moved the video record button to a more logical spot next to the electronic viewfinder, rather than on the right side, as before, where it's hard to find by feel. It also added a much-needed joystick, making it possible to change the focus area while looking through the electronic viewfinder (EVF).
The quality and layout of other buttons have been subtly changed, with slightly larger dials for aperture, shutter speed, back jog and exposure compensation. The programmable C3 button was moved to the back to make room for the video record button, and there are now 13 customizable buttons, making it easy to change preferred settings without diving into menus.
Speaking of which, Sony has improved the menu system on the A7 III, matching what it has on the A9. It's still occasionally hard to find important settings, but the system is a heck of a lot better than it used to be and nearly on par with Fujifilm's excellent X-series menu system.
The higher-resolution A7R III has a brilliant new 3.69-million-dot OLED electronic viewfinder, but the A7 III's EVF is the same as before, with 2.36 million dots. That's not surprising, considering it costs $1,200 less, but the problem is that similarly priced rivals, the Fujifilm X-H1 and Panasonic GH5s, both have similar, higher-resolution 3.69-million-dot EVFs.
Sony did increase the magnification on the A7 III's EVF a bit, but that just makes the lower resolution more obvious. It was, however, quite responsive, activating quickly when I put my eye to it.
The rear display has touch capability, but you can use it only to change focus. That's unlike the touchscreens on the aforementioned X-H1 and GH5, which also let you tweak menu settings. The new display is a bit dimmer than its predecessor's, so it can be tricky to use in sunlight, even at maximum brightness. As with all other Sony mirrorless cameras, the display only tilts and doesn't flip around -- unlike on the GH5s and certain Canon DSLRs -- so it's not very useful for vloggers who like to shoot that way.
The A7 III has a great complement of ports, including USB 3.1 Gen 1 (Type C), micro-USB, PC interface, HDMI micro, and 3.5mm headphone and microphone ports. The latter are a big selling point of the entire A7 series, as most mirrorless cameras -- including Sony's otherwise excellent A6500 -- don't have a headphone port, which is crucial for ensuring audio quality when shooting video.
As with the A7R III, the A7 III now has two SD card slots, but only one of them supports UHS-II. That's a weird choice, because you'll need to spend big bucks on a card if you want UHS-II speeds, but you won't get them when it's inserted into the non-UHS-II slot.
As for wireless control and image transfers, the A7 III comes with NFC, WiFi and Bluetooth 4.1, making it relatively easy to sync your smartphone. You'll need to install PlayMemories mobile on your device, but that app doesn't always connect reliably to your phone and is a bit laggy. To be fair, that criticism applies to nearly every other camera brand, too.
The net effect of all the changes on the A7 III's handling is more than you might except. Sony's new camera has the best ergonomics of any mirrorless camera I've tried -- after a short time with it, I could just shoot without thinking about how to change a single setting.
Technically, the Sony A7 III is a dream on paper, but the proof is in the shooting. Let's start with autofocus. The A7 III can fire bursts for a long time at high speeds (10 fps for up to 9 seconds in compressed RAW mode), but that doesn't do you much good if the focus can't keep up. The new model has 693 phase-detection points and 425 for contrast detection, a huge increase over the 117/25-point phase-detect/contrast-detect AF system on the A7 II.
Using a Zeiss 24–70 f/4.0 zoom lens with the aperture wide open, I shot bursts of our bull terrier Harpo tearing around the yard at full speed. Using the center and flexible spot autofocus, it yielded an impressive hit rate for usably sharp images. That improved when I selected the "lock on autofocus" option, which allows you to first select a subject and have the system track it automatically.
All the other modes (area, zone, extended flexible spot, etc.) also worked great. Sony's eye-tracking autofocus (activated by pressing and holding the center "select" button) is uncanny, locking onto a subject's eyes (including the dog's), even when they move around a lot. For most scenes, that means your subject's face will always be in focus.
Sony's autofocus system is deep and powerful, but my complaint is the steep learning curve to understanding and mastering it. For the next version, Sony might want to simplify the settings to reduce menu diving. Suffice it to say, if you want to get the most out of this camera, you're going to have to spend a couple of hours, at least, figuring out the AF (Sony does explain it very well here).