Synfig has not a camera support. I’ve arranged a workaround to have a camera fake using logarithm convert type and the zoom layer.
Notice that you’ll need to have minimum the revision svn r
Just download the attached file and render it with and without the zoom layer enabled. Dig it to know how I did it and ask here if have doubts. Play with the Circle layer called “Camera widget” to move the camera zoom and position. The red rectangle represents the visible area.