Nikon UW-Nikkor 2.8/20mm + DF-20 | Wide angle lens

This lens is the legendary Nikon UW-Nikkor 20mm f/2.8, an ultrawide optic introduced in 1985 specifically for the Nikonos system. Next to it, on the left, you can see its dedicated external optical viewfinder (DF-20), indispensable because the built-in viewfinders on Nikonos body housings did not cover such a wide field of view.
The entire structure is designed to withstand hydrostatic pressure up to 50 meters of depth, with thick O-ring seals to prevent any saline intrusion.