While I was taking photos during the walk, I felt something brush up against my side and looking down, saw that it was a Weimaraner. I didn't hear the dog approach me at all in the wet grass, it was just suddenly there saying a friendly, 'Hello'. I patted it on the head, looked behind and then saw the owner in the distance who waved back, smiling. He'd obviously watched his dog run off to greet me and wondered when I'd notice (as I was looking through the lens at the time)