Hi Frank.
I have the same problem as Anton. I use the camera control via the UART port from the flight controller.
For example, I set the zoom to S1 on my TX16, and when I start zooming - it stops at about half of its strength (about as Anton described - about 5x zoom) and does not increase further. In order to continue the zoom - I have to put S1 in the center position and put it back to the maximum value. You also have to do the same when you reduce the zoom.
But the main problem in all this is that the digital zoom does not work. I managed to turn it on a couple of times randomly by moving S1 back and forth, but it doesn’t work that way.
I’ve tried assigning it to different controls - the result is the same.
I would be grateful if you could help solve this problem.