Sigma aren't afraid of taking on the super-tele challenge, I hope they take a look at those prices and think "here's our chance". Personally I'd love to see Tamron have a crack at the super-teles, but they don't seem interested.
As for the 200-400, it most certainly will be more expensive than the new 300 F/2.8, so I'm predicting at least $8k now. Ouch.



