I was wandering along the runway at Concrete towards the end of the day during the fly in.  A Robinson R44 had been doing pleasure flights throughout the day and was landing well up the field from where I spent a lot of my time.  I had photographed it as it came over a couple of times but soon lost interest.  However, as I wandered along, I happened to be near his landing spot when he came back from another trip.  I was far better placed to get a shot or two so I did.  However, he spotted me and, instead of following his normal approach routine, he brought the helicopter to a hover in front of me facing at me as they all looked at me while I looked at them.  As long as I kept shooting, he didn’t go anywhere so eventually I just lowered the camera and waved.  At that point he turned around and landed.