What is Tokina doing? It’s not a brand that you would think of when buying a new lens that is going to be used underwater. I mostly use Nikon optics for it’s quality, but some Tokina’s are just as good. It seems that the Tokina 12-24mm wide angle zoom is very sharp. I bought the Tokina 10-17 (sometimes referred to as “the Tok”) fisheye zoom. Whow, what a great and versatile lens. I have not used the 10.5mm from nikon anymore since I got the Tok. That is, I have only used the Nikon with a converter behind a very small custom made domeport on my Seacam housing.