sudo apt-get install gphoto2 v4l2loopback-utils v4l2loopback-dkms ffmpeg
sudo modprobe v4l2loopback exclusive_caps=1 max_buffers=2
Connect the camera with the USB cable. You don't have to change the camera to any special mode neither run any special "App" on the camera: just turn on the camera and connect the USB cable.
On the camera display it should appear:
"Connecting...
USB"
Run gphoto2 (with acceleration):
sudo gphoto2 --stdout --capture-movie | sudo ffmpeg -hwaccel qsv -init_hw_device qsv=hw -filter_hw_device hw -i - -vcodec rawvideo -pix_fmt yuv420p -threads 0 -f v4l2 /dev/video2
Run gphoto2 (without acceleration):
sudo gphoto2 --stdout --capture-movie | sudo ffmpeg -i - -vcodec rawvideo -pix_fmt yuv420p -threads 0 -f v4l2 /dev/video2
Use your client software (jitsi or zoom or mpv):
mpv av://v4l2:/dev/video2 --profile=low-latency --untimed
[1] https://www.crackedthecode.co/how-to-use-your-dslr-as-a-webcam-in-linux/