Some folks like the 17-40Would someone please enlighten me: Why are there so contradicting opinions on the 17-40L vs 16-35L? For all other lenses folks usually seem to be able to agree on what's "better", though "is it worth it" usually is more controversial.
There is one easy example. Yes vignetting can be corrected easily enough, but on higher dynamic range scenes it won't be as much fun opening up really really dark shadows(till Canon gets Sony class shadow lack of noise sensors I guess).
I never had a problem with my 17-40 on a crop other than F4 was kinda annoying. Then I got the 10-22 and never used the 17-40 basically. Then I got a 5D II and sold my 10-22. So back out came the 17-40, where I soon hated it now on full frame. F7.1 would be the max of getting rid of vignetting, as in no improvement past that anyway, but it was still there a good bit. Need it more open like F4 and well it was just stupid. I soon found myself iso'ing up the 5D II just because I was stopped down so much. I wished I had enough money to get the 16-35 II just over that issue alone. My copy of the 17-40 on a full frame had utter crap corners, which I have heard is more common than not(many may never have much important out there or notice I guess). The 10-22 was about impossible to get flares off of. 17-40 shooting at night with street lights and voila flares for each light source.
I've never owned the 16-35 but have seen it's flare is at least worse and doesn't sound like corners are that great. Least its vignetting full frame is in a whole nother class. On my 17-40, where you see the heavier vignetting on the above link, you could count on about an equivalent sharpness drop off. It was damn nice in the middle and at least a good ways out though. Even stopped down, if I had stuff in the corners that needed to be sharp, well it was disturbingly soft.
My thought always was, if I'm going to invest the cash to go full frame, I'm going to have to invest the cash to get a lens that truly makes it worth it. I constantly kept thinking, I was better off with my 10-22 on a crop than my 17-40 on full. I had to stop down to help the extreme vignetting to get it to where the 10-22 starts, resulting in more iso noise anyway. Then I added in having flare issues I never had with the 10-22. And again, least on my 17-40 that seemed great in the center, the corners were pathetic, fine on the 10-22. It just felt stupid to have made the "jump".
So I went back to crops as I needed money then and certainly didn't have the ability to spend more for the 16-35. Since then I've made the full frame jump again for the second time and this time I went with the Zeiss 21 for my go to wide angle. Really with these wide angle zooms, you aren't getting that much focal change. A great prime like the 21 Zeiss instead made more sense. I had the option this time around to get the 16-35 and it just didn't sound so appealing.
Here's one to consider on corners as well, Zeiss at F2.8 to the 16-35 stopped down to F5.6 even. Says something about the corners of even the higher priced(than 17-40) 16-35. Weird just how bad the corner vertical lines look. http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=708&Camera=453&Sample=0&FLI=0&API=0&LensComp=412&CameraComp=453&SampleComp=0&FLIComp=1&APIComp=3
It seems to me if corners don't matter, have at either zoom. If F4 and vignetting don't matter may as well go 17-40.