yesterday I was looking into the wide angle zoom lenses that will fit the D800
I came to a list of these 7 lenses with their field of view
Nikkor AF-S 14-24mm F2.8 G ED Nano 114 - 84
Nikkor AF-S 16-35mm F4.0 G ED VR Nano 107 - 63
Tokina 16-28mm F2.8 AT-X PRO FX Nikon 107 - 77
Sigma 12-24mm F4.5-5.6 II DG HSM 122 - 84
Sigma 15-30mm F3.5-4.5 EX DG ASPHERICAL 110 - 72
Nikkor AF 18-35mm f/3.5-4.5 IF-ED D 100 - 62
Nikkor AF-S 17-35mm F/2.8 D IF-ED 104 - 62
They all seem to to have some pro's and con's (weight, price, field of view, build, aperture)
For a swim-around lens I think the Nikkor 16-35 f4 would be my top choice at the moment. The 35mm end gives you some zoom options for smaller subjects, F4 is reasonably fast, weight is 685 grams.
Curious what people are using for zoom lenses on their Nikon full frame and if they would buy the sam lens again