The iPhone a tually happens to have a quite decent camera.
Here's something I wrote about that:
If you just want to have a look at your playing technique, even the internal microphone might be good enough...
Music is a big continent with different landscapes and corners. Some of them I do visit frequently, some from time to time and some I know from hearsay only ...
My Youtube Channel is: TheMusicalEvents
My homepage is: https://www.live-arts.de