Hi! It works flawlessly, but make sure you do not exceed the maximum number of waypoints. It is also not clear if the DO_DIGICAM_CONTROL problem have been resolved in Mission Planner:
http://discuss.ardupilot.org/t/camera-trigger-problem-by-do-digicam-control/7304/4
http://discuss.ardupilot.org/t/do-digicam-control-no-longer-functions-cant-take-picutres/7636
http://discuss.ardupilot.org/t/camera-trigger-problem-by-do-digicam-control/7304
https://github.com/ArduPilot/MissionPlanner/issues/1413
So I would suggest doing camera triggering based on distance.