Zeiss Otus 85mm f/1.4 APO-Planar (about $4490) for Nikon or Canon.
In Guide to Zeiss, here are just a few of the images provided as lens rendering aperture series including HD and UltraHD images in both color and black and white renditions, along with large crops and commentary/instruction.
Each series is carefully chosen to complement the others to give a full picture of the lens behavior under a wide variety of lighting and focusing distances. With the entire aperture series, the reader can visualize lens performance in a much deeper way than single images. On a 4K display with the UltraHD images, the viewing experience is stunning.
Click each image to go to its series.