TIL, and this sounds actually rather useful.
Do you have information on which ones would support that? Especially in the range a curious hacker (who else is HN for?) would be interested in.
It's especially useful in crowd gatherings, group photos and such. I think it's rather designed for concerts, weddings, etc.
My A7-III has it. Since it uses Eye-AF and Face-AF pipelines (it generates a face model from the photo you take for that feature only), it needs AI autofocus stack inside the camera. A7-C should have it, maybe latest APS-C lines (6600 for example) have it.
Sony's AF tech is insane. Point to a person with sunglasses, and it marks the eye instantaneously. What the actual sorcery?
Well the goal is to recognize a face, not to match a specific face to a specific person. So you can train an AF model to to center focus on the center of the sunglasses. Even with the 'track these specific faces' features, since your still not trying to unique identify someone, the model can latch on to generic features like "red sunglasses, brown skin, surgical mask & this general shape".
You add up to five faces, prioritized, and it focuses to them if it recognizes in the crowd of people.