“How do I turn on face recognition in video for a7Riii/a7iii?” – a user on DPReview says.

Another user replies, “The manual states that face recognition will not work with 1080p at 100/120 fps and also when 4K output via HDMI. But I can’t get it to work on normal 4K 25/30 fps.”

In a Facebook group just for Sony a7iii owners, one user asked, “When I am in 1080 25p the face detect-AF is on but in 4K 25p, the face detect-AF is off). Is there a way to turn it on in 4K 25p”

I own two (2) Sony a7iii camera bodies and I can most definitely confirm that face detection does work when recording 4K (internal) video.

For the record, face detect-AF is available in 4K (24, 25, 30 fps) on both the Sony a7iii and a7Riii. In this blog post, I’ll show you the steps to (i) troubleshoot, and ; (b) enable so that face detect-AF is working when you record video in 4K.

Troubleshooting: Why isn’t face detect-AF working on my Sony a7Riii / a7iii?

First of all, you should be aware that face detection cannot be used in certain scenarios.

To begin the troubleshooting process, ensure that you are not in any of these settings:

  • Other zoom features than the optical zoom.
  • [Posterization] under [Picture Effect]
  • [Focus Magnifier]
  • Movie shooting with [Record Setting] set to [100p] of [120p].
  • When the S&Q [Frame Rate] is set [100p] of [120p] during slow-motion/quick-motion filming.

Also, check that face detection function has been enabled. You can do so by:

MENU > AF2 (6/14) > Set. Face Prty in AF > Face Priority in AF > On

Since you’re there, you may as well enable the sub-menu item underneath: Face Dtct Frame Dsp > On

Solution: Why isn’t face detect-AF working on my Sony a7Riii / a7iii?

The answer to why you your Sony a7iii / a7Riii does not face detect-AF when recording 4K video (24, 25, 30 fps) is because the camera has enabled proxy recording.

What is proxy recording?

Your camera has the ability to record low-bit-rate proxy movies when recording SAVC S movies. The following video explains what proxy recording is in depth:

When proxy recording is enabled, you will notice a small px symbol on your screen. With proxy recording enabled, [Face Priority in AF] will be greyed out.

To disable proxy recording (and to re-engage fact detection AF in 4K video recording), do the following:

MENU > Movie1 (1/9) > Proxy Recording > Off

Once done, you will have access to the wonderful feature of face detect-AF when recording video in 4K 24, 25, and 30 fps. You will know that it is working when you start seeing white squares popping over people’s faces.