Ubuntu – Using a digital camera ( Canon) as webcam

Here's another solution.

List of gphoto2 supported cameras: http://gphoto.org/proj/libgphoto2/support.php

You need install gphoto, v4l2loopback-utils and ffmpeg.

Then

sudo modprobe v4l2loopback

and

gphoto2 --stdout --capture-movie | ffmpeg -i - -vcodec rawvideo -pix_fmt yuv420p -threads 0 -f v4l2 /dev/video1

Now you have webcamera from your digital camera.