Two beautiflul things: one manmade and one made heavensent.
The fish eye lens is amazing in how distant and small the target appears but underwater, you really want to minimize the distance to target. It practice this often means that you hold the camera at arms length to get it as close to the target as possible with out crowding the target with your head right behind the camera and looking through the eye piece. It is easy to miss the focus you want because the center of the lens may be off the target completely and the camera attempting to find focus in empty water.
In these shots I held the camera probably a foot away from the sapphire and at arms length as I swam along. The water clarity was not great and in many cases, the backscatter from the ambient light ruined the image.
Below is one last image offering:
In mechanical and man made items, form can often follow function with pleasing results. In nature, form will also follow function but at a level of complexity that we are often taken by the beauty of the form with little appreciation for the function; if even understanding it.
I believe that many of us can appreciate the image above for any number of reasons. I also believe that certain comments and trains of discussion can detract from it as well as even render it inappropriate to share. Without respect, can there be true appreciation? If you do appreciate the image above, please show respect for it and the subject (as well as photographer).