fyngyrz: I have another perspective.
I wonder how many people are like me, where I see the f/2.8 and react "just another slow lens" and never even consider purchasing?
I want to see f/1.4 or better yet, f/1.2. /Then/ I'm thinking of cracking the cookie jar.
Half of each day, on average, is spent in the dark. And just because it's dark doesn't mean subject matter will hold still. So slow lenses are not of interest.
And before someone says "f/2.8 isn't slow", you come back and tell me that after you've shot in the dark with an f/1.2 lens like Canon's 50mm or 85mm. If you do, I'll know you haven't actually used a fast lens. :)
This however is a zoom lens and should not be compared to fast primes. "Wanting to see" f/1.4 or f/f1.2 on a zoom lens like this does not make sense, who wouldnt?. My reasoning is, if its dark, get a flash, or even a flashlight or try make your subject stay still, better yet get some skills to expose at the right moment. The lens does not do the photo, you do. If night shots is all you do theres the 58mm Noct Nikkor for Nikon, and probably a similiar for Canon. f/2.8 constant in this zoom range is FAST in my opinion
For me, "bokeh" usually translates into "censored, i want you to see this only". This is only my opinion since i do not want to spoon feed people subjects and mostly i tend to follow realism over expression, i want people to see and choose the appropriate subject in a photo. There are of course situations where the picture would get too cluttered without a certain spot focused in on. I find this f/4 a welcome addition over the gap that exists currently (2.8-5.6), enough lux power without going heavily into fast sport territory while keeping the size/weight down a bit.
How it actually performs is another story, looks damn good on paper!
Robert Soderlund: The shot presented here has no sports value in my book whatsoever, it simply shows the extreme performance of the lens, which is probably suited more to nature photography.
The expression on the face of this swimmer in that specific time tells us nothing of how he feels, yet there are some that insist on "faking" sportsmens expressions way too often, slow motion for example since the 80's showing how runners pant and how loose their facial skin is. Its all fine for fooling around, but in the end, dont we want to see the sportsman doing what he does, and not how many centimeters of water comes into his mouth at a given occasion?
Do we photographers try to make ourselves differ from others by this? Is it not the idea of photography to capture what actually happens?
No you have misunderstood, its not a photo of faking, please read my comment fully before stating "faking" out of context.
The shot presented here has no sports value in my book whatsoever, it simply shows the extreme performance of the lens, which is probably suited more to nature photography.
I shoot DX format Nikon and have not experienced what it is to shoot lenses with this great focal length, however, would not these lenses be the one where you shoot with a remote instead of hitting the camera shutter button?
Even still, the VR is probably handy especially as we are looking at 800mm here. But shooting with pressing the camera trigger is bound to produce at least some sort of shake. Does the VR really sort it out at these extremes?