Sometimes I am pretty surprised by the level of detail I see in images after I am done shooting underwater. Now granted looking through a mask into a eye piece of my underwater housing, about an 3/4s of an inch, or the 1.3 inch by 1.3 inch screen is sometimes much harder than it ought to be. The combination of today’s digital cameras and available lenses can make it very clear how much detail some animals eyes contain. Add some magnification with a diopter and what was once less than a quarter of an inch across is now much bigger.
For quite a while I was trying to shoot a pair of pipe fish that were hanging out fairly close to the bottom. One was red, one was green. Even though I had a 60 mm lens on at the time which gives a broader depth of field than a 105mm I was having quite a bit of trouble getting the two pipe fish in one image. I got a couple useable shots but then I decided to get a close as I could with the 60mm and added a subsee 10 diopter (wet lens) and see what the eye looked like. The image above is somewhat cropped but does give you a sense of the detail in the eye of pipe fish. The pipe fishes eye can swivel in all directions somewhat like a flounders eye.
For an animal that relies on camouflage to feed, it is somewhat surprising how ornate the eye of a frog fish is. Yes, it is more subtle than the eye of a pipe fish or a flounder, but its design is still interesting.
Mantis shrimp can see more bands of light than we can. Their eyes can swivel independently and move in different directions. Although I think it would interesting to be able to see as a mantis shrimp sees, I am afraid it might make me nauseous to be able to have my eyes go in different directions at one time.