Cheap and Outstanding Zeiss 25mm f2.8 ZF
D810 with the Zeiss 25mm f2.8 ZF
Every shot I take with this lens blows me away. I paid about $650 for it in mint condition (secondhand, it is discontinued). Colors are great. By 5.6 the corners are near perfect. Wide open, the center is sharp sharp sharp. It focuses so easily with the focus confirmation on the D810 (just turn the focus ring and watch the arrows). I bought it as a lightweight alternative to my zooms for landscapes. It is so small and light (relatively), yet fully metal and solid as one would expect from Zeiss.
Click the images for larger views to appreciate its ability.
Full resolution files are available on my Flickr galleries: Click here for Flickr Galleries