If you are a Canon folk and was always eyeing a way to mount the much talked about Nikon 200-400 on your cam body, look no more around. Canon announced the development of 200-400 f4 IS lens at CP 2011.
It seems like a dream lens in the making, and wildlife photographers will love it. Just make sure you start saving up for it right away. Nikon one is priced at USD 6792.00 I am sure canon will price it same (which includes the 1.4x converter worth USD ~300) if not less!
The new lens will give an effective focal length of 280mm-560mm (WOW!!). Put that on a crop body like 7D and you are looking at wild moments frozen forever.