
One-on-one calls seem to be the most consistent while adding more participants seems to throw things off. You might also have more luck with the feature in smaller FaceTime calls. Of course, pinching in reverse (pinching in) zooms back out. If the trick is working correctly, you should see your video zoom in. From here, just pinch out to zoom the feed like you would in the Camera app. Your feed will become larger, hiding other video feeds from view.

Now, double-tap your video feed to expand it. While engaged in a FaceTime call, switch to the rear camera by tapping the "flip" button. Since Apple doesn't acknowledge the feature publicly, there's no telling how long it's been a thing, but in our testing, it doesn't appear on any version before iOS 13.0. We found the feature lurking in iOS 13.5.5 beta 1 and 13.6 beta 2, but we've also successfully tested it out on iPhones running public builds such as iOS 13.0, 13.2, and 13.5.1. While there is a troubleshooting tip we've discovered, the feature itself is undeniably "in-the-works." You can't even blame the feature's failure on it being in beta.

You actually might be quite surprised to learn about FaceTime's secret camera zoom trick. And it may appear to be blocked in FaceTime too, but that's not the case - the feature is just hiding in plain sight. But in Messenger, Snapchat, WhatsApp, Skype, Instagram, and most other video chat apps, zoom functionality is disabled. With Zoom and Google Meet, you can zoom in using your rear camera on a video call to focus on something far away or to get a closeup view.
