Sigma APO 200 – 500 mm F2.8 lens
This lens (announced on the 8th of March 2007) is stated by Sigma as being the worlds first Ultra-Telephoto Zoom Lens that offers an impressively fast F2.8 maximum aperture through its range,
and oh my gosh, it looks like a beached whale attached to a tiny camera, even if you have a Mark II it’s gotta look like a fly compared to this lens!
You can read the Digital Photograpy review here: http://www.dpreview.com/news/0703/07030805sigma200500mm.asp