Sony’s A7 range has long been their most popular camera series, hitting the sweet-spot between specs and price, and on October 21st at 3pm GMT the brand new Sony A7 IV will be unveiled.
The previous Alpha A7 III is one of the best-selling full-frame mirrorless camera of all time, but nearly 4 years after it was first launched, it’s become a little long in the tooth.
Thanks to Sony themselves, all of the key specs for the new Mark IV version have already been revealed, so we can compare the two models to show you what’s changed.
With the street price of the 4-year old A7 III being significantly lower than the A7 IV at launch, why would you choose to buy the new kid on the block? We’re bringing you this in-depth Sony A7 IV vs A7 III comparison to help you choose between the two.
You can also read our detailed Sony A7 III review to find out exactly what we think of it.
The A7 III has a 24.2 megapixel BackSide Illuminated (BSI) Exmor R sensor that delivers great stills image quality and 4K video.
24 megapixels has become the sweet-spot for most recent entry-level and mid-range mirrorless cameras, with much higher megapixel counts reserved for premium flagship models.
Backside Illuminated (BSI) is a special manufacturing process that should result in better image quality in low-light situations than cameras that have a non-BSI sensor with the same number of megapixels.
The A7 IV is upping the ante by using a newly developed 33 megapixel sensor, which will presumably become the sensor of choice for all of Sony’s entry-level and mid-range full-frame cameras going forwards.
The new A7 IV uses a BIONZ XR processor, as previously found in the A7S III camera, which offers a whopping 15+ stops of dynamic range.
This processor also offers 8x more processing power than the BIONZ X processor found in the A7 III, itself no slouch.
There’s nothing to choose between the two models here, with both the A7 III and A7 IV offering ISO ranges that run up ISO 204800.
The A7 III has a native range of 100-51,200 which can be pushed two stops further to ISO 204,800, and can drop down to ISO 50 if required.
The A7 IV offers 4K UHD video recording in the XAVC S-I format, up to 60fps at 4:2:2 color depth in 10-bit to the inserted memory card or over HDMI to compatible third party recorders.
4K/30p video is oversampled from 7K, but unfortunately 4K/60p is oversampled from 4.8K in the APS-C Super 35 mode.
So when shooting in 4K at 30p, the camera utilises the full width of the image sensor to oversample from 7K’s worth of data, but at 60p, a 1.5x crop is applied.
It supports the S-Cinetone, HLG, S-Log3 and S-Log2 profiles.
There is no 4K 60p or 10-bit recording on the older A7 III.
They can both record Full 1080 HD at up to 120fps, with the dedicated Slow and Quick motion mode offering frame rates ranging from 1fps to 120fps.
The A7 IV also has quite a few features inherited from the A7S III that set it apart from the A7 III.
These include the A7S III’s AF Speed settings, no recording time limits at all, a blue peaking colour, the ability to shoot vertical videos, live streaming support, and dual NTSC and PAL recording on the same memory card without having to reformat it.
In addition, the one-touch movie button has been relocated from its rather awkward position from the rear of the A7 III to the top-panel of A7 IV.
The Sony A7 IV also supports the Digital Audio Interface (via MiShoe) to enable use of the ECM-B1M digital shotgun microphone.
The Sony A7 IV’s auto-focus system supports Real Time Eye AF for both stills and movies and also Animal Eye AF (stills only).
The Sony A7 III didn’t have these features when it originally launched, but Sony added them via the Version 3.0 firmware update at the end of 2020.
The new A7 IV has exactly the same autofocus system as the A7S III, with 759 on-sensor phase-detect points, supported by 425 contrast detect points.
It also has the recent focusing algorithm that’s the same as the one used by the recently released A7S III, which is claimed to make the already excellent AF tracking system even more reliable.
This is slightly better than the A7 III, which has 693 phase-detection points that cover 93% of the frame, plus 425 contrast-detection points, with the system working all the way down to -4EV low-light.
Once again the two models are evenly matched when it comes to continuous shooting speeds. They both offer 10fps burst shooting with Full AF/AE tracking.
There are a couple of key differences between them though.
Firstly, the A7 IV has a much larger buffer than the A7 III, especially when shooting Raw files, being able to shoot at 10fps for up to 830 JPG+RAW images in one high-speed burst.
Secondly, the fastest rate on the A7 IV is available with either the mechanical shutter or a completely silent electronic shutter – the A7 III cannot shoot silently at 10fps – which could be the difference between capturing that candid moment or distracting your subject and missing the shot.
The A7 IV doesn’t follow in its older brother’s footsteps – instead it has the same body design and heatsink system as the A7S III.
For such a feature-rich camera, the Sony A7S III remains impressively compact. It has a magnesium alloy body that only only weighs around 700g with battery and memory card installed.
Thanks to a generous handgrip the Alpha 7S III will feel very comfortable to hold.
The body has improved sealing so it can be counted upon in adverse conditions. It also features a new ‘heat dissipation’ design.
That promises no fans, no overheating, and unlimited video recording times in any resolution.
On the top there’s a shooting mode dial with S&Q option, one-touch movie record button, twin exposure dials plus an exposure compensation dial, although there is no top LCD.
It is now possible to connect an external monitor directly to the A7 IV via the new full-size HDMI port.
The A7 IV has built-in image stabilisation worth up to 5.5 shutter speed stops, the same as on the A7S III.
It also gets a new feature called Active Mode that increases stabilization for movie shooting, again inherited directly from the A7SIII.
The older A7 III also has a 5-axis in-body image stabilisation system but it’s only worth up to 5 stops.
The A7 IV has a higher-resolution, 3.69m-dot EVF that has a refresh rate of up to 120fps, the same as the one used on the A7R III and A9 II models.
This features 100% scene coverage, 0.78x magnification and a 120fps high frame rate option to help track moving subjects more smoothly with virtually no lag.
This is better than the 2.36 million dot XGA OLED electronic viewfinder used by the older A7 III, which has the same magnification but is lower-resolution and only goes up to 60fps.
The A7 IV has a fully articulating 3-inch, 1.44-million-dot LCD screen with improved touchscreen functionality, including focusing and navigating the user interface.
The A7 IV’s screen has a vari-angle design that’s been inherited directly from the A7S III, which for some users will represent a big improvement on the A7 III’s more limited 180-degree flip-up design.
You can flip out the screen to the side, rotate it forwards for easier operation when pointing the camera at yourself, and fold it flat against the back of the camera to stop it from getting scratched.
It’s simply a much more versatile screen for vlogging, movie shooting and photography in general.
The Sony A7 III was clearly ahead of its time by being one of the first mirrorless cameras to have two card slots, although only one of them takes advantage of the faster UHS-II standard.
The new A7 IV also has dual card slots, but they can now interchangeably use UHS-II SD-cards and CF Express Type A cards, just like the A7S III.
The Sony A7 IV uses exactly the same large capacity NP-FZ100 battery as the A7 III, A7C and the A6600 models.
It offers a CIPA-rated battery life of 610 shots when using the LCD screen, which is shorter than the A7 III’s 710 shot life (for the LCD screen).
Both cameras can also be powered and charged via a USB-C connection, which is useful if you’re out and about and have a compatible powerbank to plug the camera into.
The Sony A7 IV becomes the latest camera launched in 2021 to offer live streaming – 10Gbps live streaming via its USB-C port to be exact.
The much older A7 III model doesn’t offer this relatively new feature.
One of the more controversial aspects of the new Sony A7 IV is its launch price.
£2599 / €2799 / $2499 in the UK, Europe and the USA respectively is a lot more than the current street price of the A7 III, which can be picked up for around £1699 / $1799.
Whilst the A7 III has been on the market for a few years now and has naturally declined in price, we still think that Sony is being somewhat over-ambitious with the A7 IV.
Creating the successor to one of the most popular full-frame cameras of recent years was always going to be a difficult task, especially at a time of rising prices and component shortages.
A lot has changed in the four years since the A7 III was released, and it’s clear that the new Mark IV is a much more capable hybrid camera than its predecessor, on paper at least.
But it’s also substantially more expensive than its older brother, and also than main rivals such as the Canon EOS R6, Nikon Z6 II and Panasonic S1R.
So what do you think – have Sony struck the right balance between stills and video? Is the A7 IV a worth successor? Leave a comment below!