Hey, guys, I've been looking into this lens for use not only on a RED but also on my D90. How does it compare to the AF-S Nikon 28-70 2.8? I know there is a price difference, but the 2.6 f-stop is intriguing and, yes, let me say this now, I do care about every stop or half stop or quarter stop I can get, more options the better. Another concern is the image quality difference between Nikon lenses, say I use this with the Nikon 17-35 and 80-200, would it look different?