Sony has finally revealed its mainstream $2,500 Alpha A7 IV full-frame mirrorless camera and it looks to have been worth the wait. Borrowing technology from the recent A1 and A7S III models, it offers large improvements over the A7 III introduced well over three years ago. Key features include an all-new 33-megapixel sensor, 4K 10-bit 60 fps video, new AI autofocus tricks and a lot more.
The A7 IV resembles the A7S III in terms of size and layout, but you can now select between still, video and S&Q (slow and quick) options with a new dedicated dial below the mode dial. Each mode completely changes the settings and control layout of the camera to favor either photo- or video-centric controls. As with the A7S III, the video record button has been moved to a more practical spot on top for vloggers.
It comes with a 3.68-million dot electronic viewfinder (EVF) with a more comfortable 120 Hz refresh rate, up from the 2.36-million dot, 60Hz EVF on the A7 III. For videographers, the A7 IV offers a flip-out 1.03 million dot rear LCD display, making the camera far more usable for vlogging than the A7 III.
The 5-axis in-body stabilization delivers 5.5 stops of shake reduction, up slightly from before, but far below the 8 stops promised by Canon's like-priced EOS R6. However, it now offers an "active mode" for movies that helps smooth footsteps.
In terms of storage, the A7 IV offers two slots, with the top dual slot taking either SDXC UHS II (up to 300 MB/s speeds or CFexpress Type A (up to 800 MB/s), and the bottom slot compatible with SDXC UHS II only. On the A1 and A7S III, by comparison, both slots support both those formats. As for battery life, the A7 IV delivers 610 CIPA shots on a charge, compared to 700 on the A7 III.
The 33-megapixel backside illuminated (BSI) sensor provides a significant resolution boost over the A7 III's 24.1-megapixel sensor, while still offering good low-light sensitivity, Sony told Engadget. However, it doesn't offer the stacked chip-on-sensor technology of the A1 and A9/A9 II, so it lacks the sensor readout speeds of those models.
As such, the A7 IV is limited to the same 10 fps shootings speeds as the A7 III, both with the mechanical and electronic shutter — whereas the A1 can shoot at triple that speed. However, the A7 III was limited to around 90 RAW frames at a time, but the A7 IV can shoot an incredible 828 uncompressed RAW+JPEG images in a burst, provided you capture to a CFexpress Type A card.
Powered by the A1's BIONZ R processing engine, it offers the same 759 phase-detect AF points as the A1 with around 94 percent sensor coverage. It also comes with the same AI-powered image tracking that can process spatial information "in real time at high speed," Sony said. That means more tenacious tracking, along with faster and more accurate eye AF for humans, animals and birds.
Perhaps the biggest improvements with the A7 IV are on the video side. Where the A7 III was limited to 4K/30p with 8 bits of color depth, the A7 IV can handle 4K at up to 60 fps with 10 bit, 4:22 All-I capture — putting it on par with Canon's EOS R6 and the Panasonic GH5 II. 4K 30fps is super-sampled using the entire 7K width of the sensor, while 4K/60p uses a 4.6K Super35 1.5X crop. That means there's no pixel binning, so video should be very sharp.
It supports a number of video file types, including XAVC S All-I at up to 600 Mbps for 4K/60 10-bit, 4:2:2 movies. All of the video modes, except one S&Q setting that requires CFexpress Type A, can be captured to an SD UHS II card. However, unlike the A1 and A7S III, there's no support for 16-bit RAW video capture to an external recorder. RAW video isn't found on the EOS R6 either, but is available on Panasonic's $1,800 GH5s and the $2,000 Nikon Z6 II.
Video autofocus is improved with faster and more accurate tracking. The A7 IV is also Sony's first camera to support both human and animal/bird eye tracking for video. If the A7 IV's AF works nearly as well as the A7S III, it should be nearly on par with Canon's Dual Pixel AF.
What about overheating, the EOS R6's primary bugbear? With a heat-dissipating body structure, the A7 IV can record 4K 60p 10-bit 4:2:2 video continuously for more than an hour, Sony claims. The R6, meanwhile, is limited to around 40 minutes at 4K/30p before a cooling off period is required.
With most camera lenses, pulling video focus from a foreground to background subject can cause an ugly change in framing. The A7 IV's Focus Breathing Compensation system essentially uses a digital zoom to compensate for that, making the transition smoother. However, since the system needs to track lens elements, it only supports Sony-branded glass — and only the rather expensive G and GM models, at that.
If you'd rather focus manually, the A7 IV is debuting a new feature called Focus Map. It overlays colors onto a scene showing the parts within, behind and in front of the depth of field (DOF). That's supposed to help you pull focus quickly and in the right direction toward your subject. Related to that is the new "AF Assist" function borrowed from Sony's FX6 cinema camera that allows for manual focus, even during autofocus operation.
Lastly, Sony has introduced new live streaming and sharing features, though they're not quite up to the level we've seen on other recent cameras. If you use Sony's Imaging Edge mobile app, it will now use Bluetooth to maintain a continuous connection, rather than disconnecting as before.
It also offers faster transfer speeds with 5GHz WiFi and superspeed USB-C 3.2 Gen2 (10Gbps). You can do video and audio streaming over USB-C at up to 1080p 60 or 4K 15p if resolution is a priority over smooth video. That allows for webcam or livestreaming via apps like OBS with digital audio and effects like soft skin. The camera can also record internally while you're live streaming, providing a backup. Unlike Panasonic's GH5 II however, you can't transmit via RTMP to Twitch, YouTube or other services without a phone or laptop.
The A7 IV is clearly a massive leap forward for Sony's "basic" full-frame mirrorless camera series, putting it on par or ahead of most rivals. The only deterrent is the $2,500 price tag ($2,699 with a 28-70mm f/3.5-5.6 OSS kit lens), which is $500 more than the A7 III cost at launch. I'd wager, though, that it's going to be just as popular as the original, provided it delivers the promised performance — so stay tuned for our review. The A7 IV is set to arrive by the end of December 2021.