Yup, in terms of IQ, this lens just blows away the 16-35 and 17-40.
If you've still got one of those two lenses, you could try giving it away for free because they're not really worth having now.
Holy inflammatory statement Batman! Seriously....enough of the rhetoric already. For my purposes the 17-40 is a gem of a lens...but then again I just use it for landscapes between f8-f11. I'm sure the new 16-35 f4 is a great lens...and it should be given that Canon is WAY behind in providing superior quality UWA zooms, but it's not like their existing lenses are garbage.
generally agreed, although it is starting to seem, that at least on the wider end the new one is better even at landscape apertures than the 17-40 and even a touch compared to 16-35 II and not just for sharpness but for resistance to nasty purple fringing and stuff.
Truth be told the UWA zooms in the current lineup are better than most of the photogs who buy them.
Personally I think this types of statements are as silly as the other guy saying the only possible place for the 16-35 II and 17-40L is in the trash, they are useless now 100%. It's nonsense, heck we one swapped top end super-tele and 1 series with newbie sports shooters rebels and lenses and guess what the newbies some without even the best talent on top all instantly did better with the top gear. So it's silly to go around saying how most equipment is better than most photogs who buy it.
I stand by my statement...the TRUE differences in image quality between a 17-40mm and a 16-35f4 are negligible compared to the skill required to get the most out of them. Your thinking is why so many people try and 'buy' themselves Galen Rowell quality landscapes by buying the latest, greatest gear and upgrading every year...which is fine I guess if you can afford it. The fact is though that a 17-40mm is capable of providing world class imagery if you know what you're doing. You can't buy an artistic vision...
Sure, all that you've got to do is make sure that anything with detail in it is in the center of the lens, not in the corner or edges.
Problem is that when you're shooting landscapes, you've got detail everywhere that you want to keep.
That sort of restriction kind of messes with your artistic vision. Unless your artistic vision for landscape photography is limited to that of a portrait photographer.