Sony A7 III vs A7 IV – The 10 Main Differences

The A7 mark III has become the most popular full frame camera since its release in 2018. Blending excellent quality and performance at a competitive price, it made an important contribution to the rise in popularity of Sony mirrorless cameras.

Three years later, the A7 IV arrives with some very big shoes to fill. Is it the successor we’ve been waiting for? Let’s find out!

Cover image with the Sony A7 III next to the A7 IV, with the title of the article on top

More Sony A7 IV comparisons:

A7 III vs A7 IVA7 IV vs A7R IV

A7 IV vs A7S IIIA7 IV vs A7R III

A7 IV vs A9 IIA7 IV vs A7C

A7 IV vs Z6 IIA7 IV vs R6


Ethics statement: the following is based on our personal experience with the A7 III and official information about the A7 IV. We were not asked to write anything about these products, nor were we provided with any sort of compensation. Within the article, there are affiliate links. If you buy something after clicking the link, we will receive a small commission. To know more about our ethics, you can visit our full disclosure page. Thank you!


1. Sensor

The A7 III features a 24.2MP sensor and has a low pass filter. Despite sharing the same resolution as the previous models (mark I and mark II), the sensor was new and conceived specifically for the mark III model with a faster readout and back-illuminated structure (BSI).

The A7 IV comes with a brand new chip that increases the resolution to 33MP (27% increase) and uses a BSI design as well.

graphic image showing the Sony sensor

Despite the higher pixel count, the A7 IV retains the same ISO range as the A7 III: 100 to 51,200 ISO (normal range), or 50 to 204,800 ISO with the extended values. The mark IV also has a new ISO Range Limit option to reduce the sensitivity range when working in manual ISO mode (if you know you won’t use all of it for example).

The A7 IV features a faster image processor, the BionZ XR (8x time faster than the BionZ X on the A7 III, according to Sony) and it should, among other things, keep noise at high ISO more contained.

Sony BionZ XR image processor

Another welcome addition on the A7 IV is the possibility of choosing a third compression option for the RAW files, Lossless compressed. On the A7 III, it’s either compressed or uncompressed.

Finally, the A7 IV has the option to record 10-bit HEIF images in addition to JPG and RAW. HEIF provides better colour depth than JPG, but keep in mind that it is not a popular format yet, so you can encounter incompatibility with post production software programs.


2. Autofocus

The A7 III features 693 phase and 425 contrast detection points. The phase area covers approximately 93% of the sensor surface.

The A7 IV increases the AF coverage slightly (94%) with a total of 759 phase detection points. This is the same amount used by the A7S III and the flagship A1. The contrast detection points remain the same (425).

Graphic image showing the 749 phase and 425 contrast detection points

Sony says that autofocus has been improved not only in continuous mode, but also in S-AF mode, in which the phase detection points have been optimised to make focus acquisition quicker and more responsive.

Another improvement concerns low light sensitivity, which is -4Ev vs -3Ev on the older model (with an F2 lens). Furthermore, phase detection autofocus works down to f/22 on the A7 IV (versus f/11 for the A7 III) when using high continuous shooting speeds.

The mark IV model sees a significant boost when it comes to the autofocus software and machine learning. It has real-time tracking and real-time Eye AF that works for humans and animals, including birds. Eye AF works for video as well (including for animals and birds). Overall, Sony says that the accuracy of Eye AF has been improved by 30% in comparison to the A7 III.

The mark III model received Eye AF for animals via firmware update (version 3.0) but it is an older version and doesn’t work with birds. Plus, Eye AF (humans/animals) is not available during movie recording.

Lamb walking in a field
A7 III, 1/400, f/5.6, ISO 800 – FE 100-400mm GM
Captured using Eye AF

There is no real-time tracking on the mark III model, but the old tracking mode which is called Lock-On AF. The latter can provide good results but it is not as fast or as precise as real-time tracking.

One thing many users will appreciate on the new camera is the possibility of changing the colour of the focus area displayed on the live view, with a choice of white or red. You can also limit the number of Focus Area settings, so that you don’t have to scroll through all of them every time (if you know you’ll only use 2 out of 6 for example).

Another improvement on the new camera is additional controls for autofocus during video recording.

There is the AF Transition Speed that works in 7 steps to make focus transitions fast or slow, whereas AF Subject Shift Sensitivity determines how fast focus should move from one subject to another. It works on 5 levels.

screenshot of the Sony A7 IV menu, showing the AF settings for video

These settings replace the AF Drive Speed and AF Track Sensitivity settings you find on the A7 III which have fewer steps to control the performance (2 levels and 3 levels respectively).

Last but not least, the A7 IV has a new option called AF assist, which allows you to use the focus ring to make manual changes while working in continuous autofocus mode.


3. Drive Speed and Buffer

Both cameras have a maximum continuous shooting speed of 10fps, and they can maintain autofocus and exposure tracking at that speed.

The fact that the A7 IV can maintain the same speed as the A7 III despite the higher megapixel sounds good, but there are a few limitations to be aware of.

According to early tests by DPreview and Gordon Laing, 10fps can be achieved with JPGs or Lossy compressed RAW. If you select Lossless compressed or Uncompressed, the speed drops to about 6fps. Gordon also says that you need the CFexpress card to achieve 10fps with compressed RAW, otherwise the speed drops to around 8fps.

The A7 IV has a larger buffer that allows you to save more than 1,000 JPG, lossless compressed or compressed RAW, or more than 800 uncompressed RAW files. Small catch: this is valid when using a CFexpress card (more on that further down).

Series of images taken at 10fps, showed in a grid

By comparison, the A7 III can do 182 JPGs, 89 compressed RAW or 40 uncompressed RAW images, using a UHS-II SD card. These figures more or less match my personal experience and in-house tests with the A7 III.


4. Video

There are a lot of interesting improvements on the new camera when it comes to video.

First, there is no more crop with the A7 IV when recording 4K up to 30p. The A7 III uses the entire width of the sensor at 24p and 25p, but applies a 1.2x crop when working at 30p.

Cameraman holding the A7 IV with lens and microphone

Both cameras record with full pixel readout and no pixel binning. Because the A7 IV has more sensor resolution, it over-samples from a 7K area versus 6K on the A7 III. In short, the mark IV model uses more pixels to create the 4K footage, which should result in a bit more sharpness and details rendering in comparison to the mark 3 model (which is already very sharp in my opinion).

What you won’t find on the A7 III is the possibility of recording 4K at 50p and 60p. There is a catch however: to do so on the A7 IV, you have to work in Super35 mode (APS-C crop, which is 1.5x). This way, the Sony maintains the same full pixel readout and no pixel binning process (oversampling 4.8K of data).

Sunset image on the beach, with various bright rectangle overlayed showing the crop factor for the various 4K frame rate on the A7 III and A7 IV

Then we have codecs and colour depth. The A7 III can only work in 8-bit (4:2:0 internal up to 100Mbps, 4:2:2 external).

The A7 IV inherits most of the capabilities found on the A7S III. This means:

  • 10-bit 4:2:2 internal
  • 10-bit 4:2:2 external (via HDMI and compatible recorder)
  • XAVC HS codec option (H.265)
  • All-Intra compression option (H.264) with a maximum of 600Mbps
graphic image simulating the difference in compression between H.264 and H.265

The A7 III has the 30 minutes / clip recording limitation, unlike the A7 IV. With the latter, Sony claims you can record more than 1 hour of uninterrupted 4K 60p footage in 10-bit 4:2:2.

In Full HD, the A7 III and A7 IV maintain the same capabilities with a maximum of 120fps and the choice of recording with sound, or conform the slow motion / fast motion result in camera (S&Q mode).

Another thing inherited from the A7S III for the new camera is the Creative Looks. They replace the old Creative Styles found on the A7 III with 10 colour profiles designed for stills and video (the Styles are not meant for video and they often clip highlights). Each Look has 8 parameters that can be adjusted (vs 3 parameters for the Styles). There is also a Soft Skin Effect setting that, as the name suggests, gives skin tones a smoother look.

example of various creative looks images
The Sony Creative Looks

For those who want more advanced parameters, the Picture Profiles are available on both cameras and include S-Log2, S-Log3 and HLG curves. The A7 IV also gets the S-Cinetone gamma and colour mode.

Finally, there are additional settings designed for video that you won’t find on the A7 III, including:

  • Breathing compensation: it reduces the breathing effect caused when focusing from the foreground to the background, a common characteristic of photography lenses (the field of view is cropped a little as a result). Note that not all lenses are compatible. You can find the list on the Sony website.
  • Shockless WB: makes the changes in white balance more smooth during movie recording (when you change it manually). There are four settings to control the level of smoothness: Off, 1 (fast), 2, 3 (slow)
  • Flexible Exposure Mode: in video mode, you can switch between auto and manual exposure settings separately for the aperture and shutter speed, which is what you find on professional cinema cameras. This becomes an alternative to the classic PASM modes.
  • Shot Mark: you can add markers in your video clip and access them later in the video editing software (Sony Catalyst Browse or Prepare, not sure about other video editing apps).

5. Image stabilisation

Both cameras feature in-body image stabilisation (5-axis).

Graphic image showing the IBIS mechanism inside the A7 IV

The A7 III has a rating of 5 stops of compensation, whereas the A7 IV has 5.5 stops (CIPA). On paper, this looks like a minor improvement although we have to see in real world use how much of a difference there is.

What is only available on the A7 IV is the Active mode, which works for video and uses data from the camera’s gyro sensor to be more effective. It is intended to make the footage more stable, reducing the wobbling effect which is more relevant with wide angle lenses. The field of view is cropped slightly as a result (about 1.1x).

Another possibility with the A7 IV is to leave IBIS off, and stabilise the footage in post using data from its gyro sensor and the Sony Catalyst software. Reviews about other models sharing the same possibility (A7S III, A7C) show great results.


6. Design and ease of use

The A7 IV has the same design upgrade seen on the A7S III, which is very similar to the A9 II and A7R IV.

The A7 IV is a bit larger in comparison to the A7 III, and it is a bit thicker because it features a heat dissipation structure (the same as the A7S III), which allows it to record 4K video for long periods of time without overheating.

difference in size between the A7 IV and A7 III, top view
Heat sink design on the A7S III / A7 IV

Both the A7 III and A7 IV are weather sealed. 

  • A7 III: 126.9 x 95.6 x 73.7mm, 650g
  • A7 IV: 131.3 x 96.4 x 79.8 mm, 658g

The new camera has a larger front grip and buttons that should provide better tactile feedback. The video recording button is positioned on top of the camera (as opposed to the rear, near the EVF).

For the first time on an A7 camera, the exposure compensation dial can be customised, and also comes with a lock button. These two characteristics are absent from the A7 III, which has a normal exposure compensation dial with white markings on top.

Another addition on the new camera is a secondary dial found underneath the main P/S/A/M dial.

close-up on the Still / Movie / S&Q dial on the A7 IV

On the A7 III, all the shooting modes, including video, are found on the same top dial, so if for example you want to record video in Aperture priority mode (A), you have to first set the main dial to video, then go in the menu (or FN menu) to choose the A exposure mode.

On the A7 IV, you can now switch from photo to video (or S&Q) with the secondary dial, and choose any of the PSAM modes with the main dial, rather than digging in the menu. This looks like a much quicker and more straightforward thing to do if you’re in a hurry. Also, the settings and functions in the menu change accordingly when you go from photo to video mode, and vice versa.

But that’s not all, as the A7 IV has more options when it comes to customisation:

  • you can configure all the dials differently when working in Manual mode
  • you can change the function of a dial temporarily with the help of My Dial Settings plus a custom key
  • there is one extra button to customise (the top of the rear control wheel)
Screenshot of the A7 IV menu, showing how you can configure settings differently for still and video

Another thing is that you can change basic settings independently when you are in photo or video mode. This means for example that if you change the setting from F2.8 to F5.6 in video mode, the same change won’t appear when you go back to still mode (where it will still be 2.8). This possibility can be applied to aperture, shutter speed, ISO, exposure compensation, metering, White Balance, Picture Profiles and the Focus mode.

Another aspect to point out is that the A7 IV inherits the latest menu design, which is much better organised than the old menu found on the A7 III, and is compatible with the touch screen.

Now let’s move on the physical interface layout.

The A7 IV is compatible with the digital audio interface (via the multi-function shoe) which allows recording at 24-bit with 4 channels when using compatible microphones. It also has a full size HDMI port (vs Micro size on the A7 III).

Both products have a microphone input, headphone output and a USB C port. Concerning the latter, the one on the mark 4 model is 3.2 Gen2 and works at 10Gbps (versus 5Gbps on the mark 3). Also, the A7 IV can work with a wired LAN connection if you buy an optional LAN to USB C adapter.

Finally, the battery is the same for the two cameras (NP-FZ100) but the A7 III retains a better rating (CIPA): 710 frames versus 610 on the mark IV model (when using the LCD screen). Both cameras accept USB charging and power delivery.

Some original and third-party NP-FZ100 batteries

7. Viewfinder and LCD screen

The resolution of the electronic viewfinder goes up to 3.69M dots on the new camera, which is a good step forward from the 2.36M panel found in the A7 III, but is not impressive either now that several products offer 5M or even 9M dot EVFs.

The size of the OLED panel remains the same (0.5-in), as does the magnification (0.78x) and the eye point length (23mm). On the A7 IV however, you can boost the refresh rate to 120Hz, whereas on the older camera it doesn’t go beyond 60Hz.

The A7 III has an LCD screen that can tilt up and down, whereas the A7 IV has a vari-angle mechanism that allows you to flip it to the side and rotate it 180˚.

side view of the Sony A7 III with the LCD screen titled

The resolution of the rear monitor is similar (0.92M dots for the A7 III, 1.04M dots for the A7 IV) and they are both touch sensitive. Regarding the latter, there is more you can do with the A7 IV, including navigating the menu. On the mark III model, the touch screen’s main purpose is to move the AF area.

hands holding the A7 IV with the screen opened on the side

8. Memory cards

Both cameras feature two memory card slots that accept SD cards. On the A7 III, slot nb.1 is UHS-II compatible, whereas slot nb.2 is UHS-1 only.

On the A7 IV, both slots can work with the faster UHS-II SD cards and, what’s more, slot nb.1 also accepts the CFexpress Type A card, which provides faster writing and reading speed, and gives you a larger buffer memory, as explained previously.

Memory cards next to the Sony A7 IV

The card door has also been redesigned with a more robust unlocking mechanism on the new camera.


9. Extra features

The A7 IV has a lot of extra settings and features you won’t find on its predecessor. Here are some of the most interesting.

  • Focus Map: it gives you a graphic visualisation of the depth of field, highlighting in red what’s behind the DoF and in blue what’s in front of it. The areas where colours remain normal are within the depth of field.
  • Variable Shutter: you can adjust the shutter speed to a much higher degree of precision than 1/3Ev, and see in real time the impact it has regarding flickering (with artificial light sources). It provides more precision than the Anti-Flicker Shooting mode, and allows you to detect flickering at frequencies higher than 100Hz or 120Hz (LED lights for example). It works for stills and video.
  • Anti-dust Function: it allows you to keep the shutter curtains closed when the camera is powered off, to protect the sensor from dust when changing lenses for example. This is a copy and paste idea from the Canon EOS R.
  • USB Streaming: you can use the camera as a webcam with the USB C connection, after selecting the streaming option in the menu. No extra software or plugin required (unlike for the A7 III). It works up to 4K 15p, or 1080p 60p, and you can record simultaneously on the memory card.
V-logger pouring sauce on pancakes in front of the camera connected to  a laptop
  • Wireless LAN: it works at 5Ghz, as opposed to 2.4Ghz on the A7 III.
  • RAW transfer: you can send RAW files, in addition to JPGs, to your smartphone.
  • FTP transfer while shooting: you can connect the camera to a server via wifi, wired LAN (with USB C adapter) or a USB tethered smartphone, and send images and video files while working. For the A7 III, only the wifi option is possible.

10. Price

The A7 III can be found for $1700, £1700 or €1950. Its original launch price was $2000.

The A7 IV is more expensive, available for $2500, £2400 or €2800.

Note: prices are for the body only and as of late October 2021.


Conclusion

I bought the A7 III for review purposes when it came out in 2018, and I still have it at the time of publishing this article. It is probably the camera I’ve written the most about on this website, and it stars in many of my in-depth comparisons. I’ve often used it for personal work, but also for occasional jobs (partially because I have a good set of E-mount lenses, but also because it’s a very reliable tool).

Its successor, the A7 mark IV, looks like a worthy upgrade.

I’m already familiar with the design because I’ve tested the A7R IV and A9 II, so I can already say with confidence that I will like the new model better when it comes to ergonomics, and the extra customisation is also welcomed (although the A7 III is already good at that).

I’m curious to see how the new sensor performs, and I can certainly see myself putting those extra megapixels to good use. I can’t wait to test the more advanced autofocus system and see how it ranks in my birds in flight test, among other things. One small disappointment is about the maximum burst of 10fps, which seems to require the more expensive CFexpress card and works with lossy compressed RAW only.

Video-makers will be pleased to know the A7 IV can record 10-bit internally with a variety of codecs. Other will be disappointed that the only way to record 4K/60p is with a 1.5x sensor crop.

That said, I think the A7 IV is a very competitive camera overall. The price has increased, which is a shame, but the same can be said about other camera models as well. Personally, as a long time owner of the A7 III, I couldn’t resist pre-ordering the new model, and I can’t wait to start testing it.

Check price of the Sony A7 III on
Amazon | Amazon UK | B&H Photo | eBay

Check price of the Sony A7 IV on
Amazon | Amazon UK | B&H Photo | eBay

Second-hand Sony gear on
MPB US | MPB UK


More Sony A7 IV comparisons:

A7 III vs A7 IVA7 IV vs A7R IV

A7 IV vs A7S IIIA7 IV vs A7R III

A7 IV vs A9 IIA7 IV vs A7C

A7 IV vs Z6 IIA7 IV vs R6