A very Zeiss Mushroom
D800 with the controversial Zeiss 25mm f/2.8.
This lens has a lot of field curvature, so it does not render flat architectural walls well. It is more of an "artistic" lens.
One thing this lens will do is focus as close to 6mm to the front lens. The field curvature gets pretty extreme at this distance, but the depth of field (or lack thereof) can be extraordinary.
This is straight out of the camera, handheld, under natural light at f/11, with zero post processing (I want you to see it in the raw). What fun!
Here is a 100% crop of that image. The Zeiss detail is excellent. You can get some extraordinary performance from some of Nikons best glass, but the Zeiss adds just a bit more dimension and microcontrast to the image. The difference is arguably subtle, but there nonetheless.
This lens is growing on me (it's borrowed), but I think I will want to add one to my bag since most of my shooting is with nature/landscape. If you are not shooting walls at close distances, this lens is a $1,000 bargain when hooked up to a D800.