My first post with this lens, a little guy who was on my bed last night. He was rather resistant to moving, so he became a model. Sadly, when I went to evict him in earnest, I found he had long since passed.
This was shot on a 5D2 with a Kenko 2x TC at minimum focus distance (manual focus with focus-confirmation. I used an Alien Bees ABR800 ring light to get the brightness for the shot:
This was JUST barely resized down from a 100% crop - the original crop was 1159 on the long edge to the 800 on this image. I did apply sharpening, but as anybody who's tried to sharpen a blurry image before knows, it just calls attention to a lack of sharpness. I still intend to pick up some extension tubes, but this does a fantastic job given the compromises a 2x TC puts on a lens, especially one like this!