I just received my 100-400II along with the 2xIII today. Here's an 800mm moon shot that I took this evening, for additional comparison. This is probably about 70% crop or so, and I did play with it a bit in Lightroom just to see what it was capable of. This was from an aluminum tripod, 10 second countdown, 1/13s exposure, f/14. I manually focused it with 10x live view, keeping IS on until I was ready to take the shot. I think it came out pretty well and so far I'm pretty impressed with the few shots I'm seeing using the 2x. I'm hoping to get out this weekend and really try it out with some wildlife.