The Sony a7 IV is the fourth generation of the company’s core a7 full-frame mirrorless camera model. It’s the most advanced yet, bringing many of the improvements Sony has made in terms of autofocus and interface design since the launch of the a7 III, back in February 2018.
- 33MP BSI CMOS full-frame sensor
- Up to 10 fps shooting in lossy Raw with extensive buffer
- In-body stabilization rated up to 5.5EV
- Full-width oversampled 4K from 7K, up to 30p
- 4K/60p with Super35 / APS-C mode
- 10-bit video or HEIF stills capture
- H.265 video, S-Cinetone color mode
- 3.69M dot OLED viewfinder
- Twin card slots (1x CFe A/UHS-II, 1x UHS-II SD)
- Full-time Bluetooth LE connection
The a7 IV sees just about every one of its specifications improved over the a7 III, from basics such as the resolution of the sensor and viewfinder to significantly increased video capture options.
The a7 IV will be available from late December 2021 at a recommended price of $2499, a $500 increase over the launch price of the a7 III.
33MP BSI-CMOS Sensor
At the heart of the a7 IV is a new 33MP BSI-CMOS sensor. This represents a move away from the 24MP chip used by the a7 III and its immediate Panasonic and Nikon rivals. Given that BSI sensors are already widely used in the current generation of cameras, we’re not expecting huge leaps forward in image quality. A slight uptick in detail and comparable low light performance is the most likely thing we can expect, in terms of image quality.
Despite the higher resolution, the a7 IV can still shoot at 10 frames per second. However, it can only do so in the lossy compressed format if you want to shoot Raw. The a7 IV has a lossless compression option, for when you need maximum processing flexibility, but the burst rate drops to around 6 fps if you use it. Sony says the camera’s buffer depth allows over 800 Raw+JPEG images (or over 1000 JPEGs), but this is in the uncompressed Raw format, which again shoots at around 6 fps.
Our first look at the rolling shutter rates suggest this isn’t an especially fast sensor. 14-bit readout of the whole sensor for stills takes around 1/15 sec (~66ms), which is around seventeen times longer than the super-fast a1 takes to read out its sensor. This means silent shutter mode is likely to result in significant distortion with moving subjects.
Silent shutter mode is likely to result in significant distortion with moving subjects
Full-width 4K video takes around 26.5ms, which is comparable with the other models in its class. It’s likely the camera is dropping to 12-bit readout for video mode, but the process of combining pixels should reduce noise and hence prevent DR dropping to ~12EV. 60p footage has rolling shutter rate of around 12.8ms, which is low enough to avoid distortion of all but the fastest movement.
In terms of autofocus, the improvements over the a7 III should be fairly significant, not so much because of the promise to focus in conditions that are one stop darker (–4EV with an F2 lens) but because that camera was one of the last Sonys that didn’t integrate Eye AF into its main AF system, and relied on a much more primitive AF tracking system. The a7 III could detect human eyes, but it couldn’t seamlessly and dependably switch between eye, face and body tracking, if you set the camera to focus on a person.
The a7 IV does exactly this, and has modes that can detect and more accurately track animals, include birds, dogs and cats. For the first time, these animal detection capabilities extend to the camera’s video mode, too.
The simplicity of the system makes it difficult to convey just how effective it is. But like Canon’s latest AF system, you need only indicate to the camera what you want to focus on and it’ll use the most appropriate of its powerful AF algorithms to maximize your hit rate. Until you’ve used a system like this, or the comparable one in recent Canon cameras, it’s difficult to appreciate how powerful, reliable and simple they can be.
The a7 IV adds a Breathing Compensation mode that crops and resizes the video to cancel-out any change in a lens’s angle-of-view (AoV) as it focuses. The mode only works with select Sony lenses (all the GM lenses and some G series glass), as the camera needs a profile of the breathing characteristics. Video is cropped to match and maintain the narrowest AoV that might occur if you focused from minimum focus distance to infinity, meaning there’s no distracting change of framing as you refocus.
After autofocus, the biggest area of improvement is in terms of video capability. The a7 III was the first a7 model to offer 4K capture. Its implementation was pretty good for early 2018, with oversampled 24p capture from the full width of its sensor but a crop required for 30p shooting. All footage was captured in 8-bit precision, at relatively modest bitrates.
The a7 IV moves things forward considerably, adding 10-bit capture to increase the processing flexibility of Log footage and to allow full Hybrid Log Gamma (HLG) capture for playback on HDR TVs.
It also gains the ability to shoot 4K/60p for action capture or slow-mo work, but this requires a crop to APS-C/Super 35 dimensions. There are also options to use H.265 compression (XAVC HS) and apply the S-Cinetone color profile.
Eye AF is now available in video mode, which should substantially increase the degree to which you can depend of autofocus staying on your chosen subject. As in stills shooting mode, the camera has been trained to recognize humans, animals and birds.
However, while you can set video mode to use different color and white balance settings, define separate button setups and Fn menu layouts for stills and video, the camera still carries its exposure settings over from stills to video shooting, which isn’t always ideal.
|A fully articulating screen can be useful for waist-level shooting, vlogging or selfies. It also allows you to monitor the camera if you’re using its streaming mode.|
The a7 IV also offers the ability to live stream video over its USB connection using the audio and video standards (UVC/UAC) that are part of the USB standard. This allows a choice of HD or FullHD resolutions with FullHD available at up to 60fps. There’s also a 4K option but this only supports 15 frames per second, which gives a dreadful stop-motion look to the footage. Connection is designed to be as simple as possible, using the Imaging Edge Webcam software for Mac or PC. A connection via smartphone is also possible, though audio may not be available at resolutions above HD (720).
HEIF 10-bit stills
The a7 IV gains the ability to capture 10-bit compressed images, rather than just the 8-bit JPEGs historically offered. Unlike Canon, which only uses HEIF capture for HDR images, the Sony lets you shoot standard DR images in 10-bit, with a choice of 4:2:2 or 4:2:0 chroma sub-sampling, if you can find benefit to doing so.
The downside of this added flexibility is that you need to engage HEIF capture before you can engage the Hybrid Log Gamma (HLG) color/gamma mode, rather than having both settings change to match one another. It’s worth trying, though: images shot in HLG can show much more of the camera’s dynamic range to give a much more lifelike version of your image, if viewed with an HDR-capable TV.
How it compares
The a7 IV becomes the most expensive iteration of the a7 model yet, with a price that makes it among the most expensive of its peers. We’ve lined it up next to the similarly priced EOS R6 and the significantly cheaper Nikon Z6 II. Panasonic’s Lumix DC-S5, which we didn’t have space to include, offers a pretty similar video spec (10-bit 4K capture, including 60p from its APS-C crop) but its autofocus isn’t quite as effective. Like the Nikon, thought, it’s markedly less expensive.
We’ve included the a7 III to show what the a7 IV gains over its predecessor but there’s also the smaller, less expensive a7C that shares most of its specs with the a7 III. The only major difference is that the a7 C has a slower flash sync speed and a smaller but higher resolution viewfinder. The a7C has a newer AF system than the a7 III, so its performance and usability will be a little more like that of the new camera.
|Sony a7 IV||Canon EOS R6||Nikon Z6 II||Sony a7 III|
|MSRP at launch||$2499||$2499||$1999||$1999|
|AF system||On-Sensor PDAF||
|On-sensor PDAF||On-sensor PDAF|
|Image stabilization||5-axis||5-axis + sync with lens IS||5-axis||5-axis|
|CIPA rating||Up to 5.5EV||Up to 8EV||Up to 5EV||Up to 5EV|
|Maximum frame rate||10 fps (lossy Raw)||12 fps mech shutter
20 fps electronic
|Flash Sync speed||1/250 sec||1/250 sec**||1/200 sec||1/200 sec|
res / mag
|2.36M dots / 0.78x|
|Rear screen||1.04M fully-articulated touchscreen||1.62M-dot fully articulated touchscreen||2.1M-dot tilting touchscreen||0.92M-dot fully articulated touchscreen|
|Top-plate settings display||No||No||Yes||No|
|Video capture||UHD 4K 30p
UHD 4K 60p
|UHD 4K 60p
|UHD 4K 30p
UHD 4K 60p
|UHD 4K 24p
UHD 4K 30p
|Log/HDR modes||S-Log2 / 3 / HLG
|S-Log2 / 3 / HLG
|Memory cards||1x CFe Type A / UHS-II SD
1x UHS-II SD
|Dual UHS-II SD||1x CFexpress B
1x SD (UHS-II)
|1x UHS-II SD
1x UHS-I SD
|Battery life (CIPA) LCD/EVF||580 / 520||510 / 380||410 / 340||710 / 610|
|Dimensions||131 x 96 x 80 mm||138 x 98 x 88 mm||134 x 101 x 68 mm||127 x 96 x 74 mm|
|Weight (CIPA)||659 g||680 g||675 g||650 g|
* When shooting 12-bit Raw using a single AF point
** In electronic first-curtain mode: 1/200th with mechanical shutter
This table should make clear that the a7 IV is well specced, but not to the point of standing out from its less expensive rivals. As such, it’s going to be the real-world performance of the AF system, the degree of rolling shutter in its 4K footage, and its ability to maintain its 10fps burst rate for many hundreds of images that will need to set it apart.
Body and controls
|The shoulder dial (with the toggle-lock shown in its unlocked state) controls exposure comp by default, but is now unmarked and can be set to control other functions.|
The a7 IV appears to share its body with the a7S III, which offers a series of refinements over the previous a7 model. The grip is slightly deeper, the joystick on the back is improved and there’s a full-size Type A HDMI socket on the side of the camera.
A further improvement over the a7S III is the move to an unmarked lockable dial on the shoulder of the camera, meaning it can be re-purposed if you don’t shoot in a manner that requires exposure compensation.
There’s also a fully-articulating rear screen. These aren’t to everyone’s taste but allow video, vlogging and selfie shooting in a way that a tilt-out screen doesn’t.
The a7 IV still offers twin card slots: both accept UHS-II SD cards with the upper one also able to take one of Sony’s small CFexpress Type A cards, which can maintain much faster write speeds than the fastest SD cards (typically 400MB/s minimum sustained write, vs 90MB/s minimum sustained write for V90 SD cards).
More than the ergonomic changes, we’re delighted to see the a7 IV gain the improved menus and expanded touchscreen utilization first seen in the a7S III. The menus now have their section tabs down the left-hand side of the screen, meaning you’re only ever a click or so away from being able to jump between tabs. They’re also touch sensitive, so you may not need to click or nudge anything at all.
This layout makes the menus much quicker to navigate, as do sub-section headings within each tab. The arrangement differs from previous Sony cameras but the underlying relationships between settings remain the same, so it shouldn’t take too long to familiarize yourself with the new system, if you’re an existing Sony user.
Constant smartphone connection
Sony has offered Bluetooth on its cameras for many years but has used it solely for transferring location data from smartphones. The a7 IV adds a constant-connection option of the type offered by most of its rivals. This means you only have to pair the camera with your smartphone once, after which they will automatically re-establish a Bluetooth Low Energy connection, making it much quicker and simpler to transfer images to your phone.
The a7 IV gains the ability to close its mechanical shutter when the camera is turned off, helping to prevent dust build-up on the sensor. Shutter blades tend to be very lightweight, which also means they can be pretty fragile, so this should be seen as a dust prevention, rather than physical protection measure.
The a7 IV uses the same NP-FZ100 battery as the a7 III and other more recent Sony cameras. It’s a usefully hefty unit that, combined with the relatively modest viewfinder res, lets the a7 IV achieve a CIPA battery life rating of 580 shots per charge using the rear screen and 520 shots per charge using the EVF.
As always, these figures are more useful for comparing cameras, rather than getting an idea of exactly how many shots you’ll get (in our experience, getting double the rated number isn’t unusual with a new battery). We tend to find a rating of over 500 shots per charge means not really having to worry about battery life in anything but the most intensive pro sports or wedding shoots.
As you might expect of a new camera, the a7 IV can be either charged or powered over its USB-C socket.
Much has changed in the eight years since the original a7 was launched: with Sony now far from alone in offering a modern full-frame mirrorless camera. Technology has made huge leaps forward, too, with autofocus in particular improving in terms of speed, sophistication and simplicity, to the point that no one would now suggest DSLRs retain the upper hand.
Sony’s move to bigger batteries has had a huge impact on its cameras’ usability, and its ergonomics and user interface have been radically improved with each iteration. The video features have also expanded significantly, with the fourth a7 model bringing the series back into line with its competitors.
|Sony FE 35mm F1.8 | F3.5 | 1/160 sec | ISO 100
Photo: Richard Butler
What’s clearly changed, in the meantime, is the positioning. The original a7 was launched at what was then a record low price for a full-frame camera: $1700, body only. Even taking inflation into account, that’d still be a hair under $2000 in today’s money. The a7 IV’s price is a significant increase over this, and it’s notable that Sony now offers the a7C for more price or size-conscious buyers. This provision of a relatively up-to-date sister model, rather than simply lowering the prices on outdated models is a welcome change. The a7C might not have the improved menus of the a7 IV but it doesn’t feel as unrefined and clunky as the Marks I and II do, by comparison to the latest cameras.
Owners of the first two a7 models, and even some a7R series users are likely to be stunned by how far the series has come in the past few years
This move allows the a7 IV to address the needs of more dedicated enthusiasts, and makes it a direct competitor to Canon’s very likable EOS R6. On paper, at least, it doesn’t go far beyond the Canon, though, so it’ll be interesting to see how they compare in real-world use. Of course, if Sony decides to continue the a7 III at a lower price, the waters get significantly muddier. The a7 III’s autofocus is recognizably more than a generation behind the new camera, but it isn’t made to look like a work-in-progress, the way that the older models were when the Mark III arrived. The a7 III still does very well at most of the things the a7 IV does, which could undermine the attempt to push the series upmarket.
Sony seems very keen to say that the a7 IV has gained many of its improvements from the flagship a1, which we think that risks implying a closer connection than actually exists. While it is not untrue that the a7 IV has some features that arrived with the a1, the new camera doesn’t have the Stacked CMOS sensor that provides the brute power underpinning the a1’s performance. In many instances, it’s fairer to point out that the a7 IV’s features are shared with the video-centric a7S III. Still not a bad thing to be able to claim, but perhaps setting more realistic expectations, in terms of how much star quality you expect to rub off on the more mass-market model.
Overall the a7 IV looks to be a very capable camera: one with much-enhanced video and more sophisticated autofocus. For newcomers the increased price, an array of credible rivals and the high bar set by the a7 III means it’s going to have its work cut out if it’s to stand out in the way earlier a7 models did. However, owners of the first two a7 models, and even some a7R series users are likely to be stunned by how far the series has come in the past few years.
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