D800 + Nikon 28-300 ED F3.5-5.6G corner of images darker

Lens review sites like photozone.de amongst many others list vignetting as a quality that is measured on various lenses. So you can see how it performs with regards to vignetting for different lenses.

My experience though is vignetting is not an issue with any of the listed lenses suitable for a D800 as it is so easily corrected in software.

28-300 is generally regarded as a very convenient but soft lens just so you know.

Greg.