Detect when builtInTripleCamera changes lenses?

Question

Background: I'm working on an app that uses videoZoomFactor to zoom in on the camera view by a specific, user-specified amount. I'd like to incorporate using the telephoto and ultra wide lenses.

I implemented builtInTripleCamera, where the switch is handled quickly and automatically. It works really well for the transition between the ultra-wide and wide, but going from wide to telephoto introduces a jarring position change. This wouldn't be so bad on its own, but it happens about a second after my videoZoomFactor change is complete, so there's a zoom in focal length followed by a change in position.

Update: I've also found this happens when the camera is focused on a nearby object and decides that I want to use the macro lens.

So my questions are:

1. is it possible to smooth out the position change when using builtInTripleCamera? Apple clearly uses some tricks to avoid it in the stock camera app, is that accessible somehow?
2. if not, is it possible to detect when the position change is happening so that I can make my zoom factor change happen at the same time? Perhaps with a notification?
3. if not, I’ll probably have to stick with manual switching. In that case, is there any way to improve the speed of manual switching to get closer to how builtInTripleCamera works?

If relevant, the code I'm using for manual switching is here: https://stackoverflow.com/a/54757886/11274269

Answer 1

we solved this by manual switching with animation of opacity