That cost a bit of time, but not because someone was coming by all the time: Between the location of the camera and me there's a three minute walk due to a steep wall in between. Then I did not know that the timer clock for the serial self timer works with the time of day, not with "minutes after activation", which resulted in once walking in vain. Then the battery was dead, so it took another ten minutes to get a fresh one until I finally could start.