I know the version two is sharper, has better flare control, and better IS, etc. I am only concerned about the sharpness across the range. I can get a new/semi new version 1 for 1500usd and was wondering if version 2 (which is 2100usd) really makes that much of a difference in terms of sharpness? The lens will be paired with a 5DIII and will be used to shoot wildlife, portraits, events. No sports. Go for the version one or get version two?