A very nice photo.At first I did not even realize it was taken with a full frame fisheye but then I saw the curve on that one sapling and I went, "Aha, fisheye!"
I have a 16mm Nikkor and I never get tired of taking photos with it. It is the most fun lens in my bag.
This is the first fisheye I have owned. When you get the angle just right you can make telephone poles look like boomerangs. Even with a 180 degree coverage, the horizon is still surprisingly flat. It's hard not to get your feet in the picture!