The Nikkor 16-35 f4 is more expensive but no better. All lenses of foreign manufacturers to compare to Photo Zone, etc. visually rather disappointing. I've been searching for a suitable wide-angle zoom for my D800, and quickly it was clear: The perfect into the corners sharp lens, there is apparently not (except the 14-24 Nikkor). As prime lenses still get the Zeiss Distagon 18mm and 21 mm in question. The 21 mm wide-angle offers me too little, the 18 mm is also not much better.
I had the predecessor of Nikon AF-S Nikkor 18-35mm 1: 3,5-4,5G ED, AF-D Nikkor 18-35 1: 3.5-4.5 ED IF. This is in direct comparison clearly worse and is not recommended on the D800. In the new model, the corners cut dimmed significantly better. They are still not perfect, but its predecessor was just visibly worse in sharpness and chromatic aberration. Since I mainly ablichte landscapes, the distortion for me is not important. The chromatic aberrations have disappeared with one click in Lightroom.
By the way. I was also with all the old Nikon lenses dealt (AI, AI-S, AF-D). None of these old "treasures" seems to deliver really good results on the D800. The loss of sharpness towards the edges seem to be a common problem.
In summary, there are on this lens at 18mm is no real alternative, if 21 mm are also in order, I would take the Zeiss Distagon 21mm ZF.2, which is actually in the corners better.
Ah yes, the processing is perfectly fine, is holding plastic (but one of the better sort). Who knows Nikon, knows what to expect. I am happy.
"Only" 4 stars because it's just still has blurring in the corners. But as I said, much better it seems currently not to go.
