<Dons disgruntled spec sheet fanboy costume>
What? Canon can't get the 200-400 F4 L 1.4tc lens to market after more than a year of talking about it and now Sigma has a 200-500 AND its F2.8 ?!?!?!?!? Canon is so out of touch. How can they do this to us? They must think we are dogs and will just eat anything they feed us. No worse, they think we're dog FOOD!
I'm burning all my gear and switching brands.
<Doffs disgruntled spec sheet fanboy costume>
On a serious note...that thing is a beast. I wonder how it would work as a telescope. That would work out to a 7" F2.8 refractor....
-Brian