Just as large as this lens is the word Super fits it just fine. Personally I think this is a great lens for not only birding or any other kind of wildlife at a distance but also for artistic touches.
I took this photo Saturday night. This tree is approximately 20' from my back door. The color in the background is a street that is lit by sodium vapor lamps.
The next morning my brother took these two shots of the frost on the deck rails. Again, this is as well as all photos in this post are with the 400mm lens. Shot was taken at about a 14' distance.
It's all about the color in the fall and this lens lets you capture it with no problem. I lightened it just a bit but otherwise I really like the way it pulled the red, magenta, yellow and gold out.
Almost done, sitting on tripod and changing the focus from the maple tree in the foreground to the pine tree in the background. The maple was 35' or so out and the pine tree is 50 yards or better on the other side of a road that runs behind our house.
Lastly, on Saturday night I was able to catch all the bats and witches flying out after a wicked Halloween night in the area. They heard that there season was over and the kids were still bouncing off the walls from all the candy they had collected. No worry, they will be back next year for another round of ghosts and goblins.