DSLR as Webcam

sudo pacman -S gphoto2 v4l-utils v4l2loopback-dkms ffmpeg

sudo modprobe v4l2loopback exclusive_caps=1 max_buffers=2

sudo nano /etc/modules
# /etc/modules: kernel modules to load at boot time.
  #
  # This file contains the names of kernel modules that should be loaded
  # at boot time, one per line. Lines beginning with "#" are ignored.

  dslr-webcam

sudo nano /etc/modprobe.d/dslr-webcam.conf
# Module options for Video4Linux, needed for our DSLR Webcam
alias dslr-webcam v4l2loopback
options v4l2loopback exclusive_caps=1 max_buffers=2

gphoto2 --stdout --capture-movie | ffmpeg -i - -vcodec rawvideo -pix_fmt yuv420p -threads 0 -f v4l2 /dev/video0  
  
https://www.crackedthecode.co/how-to-use-your-dslr-as-a-webcam-in-linux/