I'm somewhat limited to vendors. B&H Photo. The 2.8 lens is $626 more then the 4. (new) Not that it's all too much of a real concern but... This $1600 lens is going to be attached to a $800 camera? it's hard to justify, granted some time in the future i'm sure i will upgrade cameras, and canon has been loyal to the ef lens for quite some time now, but...it's a lot of loot yo...i'm going
edit:
i know i will love this lens...