Linux distros may only seem lacking support for complementary software that allows full control of the hardware.
But more often than not, you can find quite decent command-line software to control the hardware.
Webcams are no exclusions to this. You can use excellent v4l2-ctl to control your webcam.
Here’s how to do it with CentOS/RHEL 8:
sudo dnf -y install https://extras.getpagespeed.com/release-latest.rpm
sudo dnf install v4l-utils
List detailed information about video devices:
v4l2-ctl --all
Zoom:
v4l2-ctl --verbose --set-ctrl=zoom_absolute=10
Disable autofocus:
v4l2-ctl --verbose --set-ctrl=focus_auto=0
Set manual focus value:
v4l2-ctl --verbose --set-ctrl=focus_absolute=1
You can do far beyond that, depending on your specific webcam features. Just take note of parameters available in the -all command output,
and adjust as needed.