The autofocus is fast and works accurately in the situations I have used it. If you are primarily using the lens for star photography, you might want to learn when it is focused to infinity either manually or with the autofocus in vast landscapes. If there is a small light source in the scenery, the lens can focus to it in most of the cases. In pitch black situations, I recommend using the manual focus. Thanks to an AF-S drive (Silent Wave Motor) autofocus operations are fast and almost silent.
Optics & Sharpness
I have used many different wide-angle lenses in my past, but with the full-frame camera I have used the Nikkor 16–35 mm f/4.0 VR, Samyang 14 mm f/2.8 and the Nikkor 14–24 mm f/2.8 G ED.
Distortion is moderate when compared to the heavily distorted photographs taken with the Samyang 14 mm. The barrel distortion is really easy to fix in Lightroom with the correct lens profile for the Nikkor. The real advantage of the Nikon 14–24 mm f/2.8 against the Samyang is the sharpness of the images overall image quality. Against the Nikkor 16–35 mm f/4.0 the sharpness is better already wide open and the extra stop is essential when you photograph in low light situations.
You can see a couple of example photographs taken with Nikon D810 and Nikkor 14–24 mm f/2.8. The images shot in RAW and exported with Lightroom CC: View the full-size gallery here.
From corner to corner the sharpness is very good already from wide open. I used two different 14–24 mm f/2.8 lenses and I have also used two Samyang 14 mm f/2.8 lenses. The Samyang focus seems to change in different parts of the image. For example, if the corners of the image are correctly focused the center is not in focus. This is not the case with the Nikkor, once you nail the focus the whole image is razor sharp.
I have gathered below some of my favorite photographs taken with the Nikkor 14–24 mm f/2.8 lens in the past month with the lens. If you are into star photography, make sure to check out my Star Photography Masterclass eBook.
Series of photographs captured with the Nikon D810 and Nikkor 14–24 mm f/2.8 G ED