Did you see a shark? - underwater photography

PSA Journal, July, 1990 by Beverly Schultz

An object underwater appears to be about one-fourth closer and about one-third larger than it actually is. We had to learn to calculate "three apparent feet," which was actually four feet. Luckily, the camera lens (because it is behind a glass port) is also affected by this phenomenon. We are affected by this phenomenon because our eyes are also behind a glass port, our masks. We spent the first few dives shooting at "three apparent feet" with either a 35mm or 28mm lens.

The visibility and brightness at depth in the Caribbean is well-known; nevertheless, it surprised me. I found exposures usually ran about f8 or f11. Using the underwater 35mm lens at f11 focused at three feet allows no more than a foot miscalculation. We had to keep in mind the Nikonos is not a reflex camera, and all distance measurements are done by guesstimate.

The names at our dive locations were descriptive of what we would find there. At Sponge Point, we could expect to see large sponges of many shapes--barrel shaped, tube shaped, to suggest two. The Wall was just that, a steep drop-off which bottomed out at 6,000 feet. Large Gorgonians, (huge sea fans with sturdy trunks up to several inches thick) graced the edge of the Wall, and made marvelous shilhouettes against the blue sea.

It was here, at the Wall, I had my first flirtation with nitrogen narcosis. A grand feeling comes over you; you are floating free...mysteriously held up...you have an overview of a fluid blue-green world. This euphoric feeling tempts you to stay, and to explore even deeper. Nitrogen narcosis is not completely understood. However, the effects can be compared to alcoholic intoxication. There are differences but the effects of nitrogen narcosis and drunkenness have much in common. The relationship to alcohol has been expressed in what might be called Martini's Law. The mental effects of each additional 50 feet of depth, breathing air from your tank, are approximately equivalent to those of one dry Martini, assuming your stomach is empty. I enjoyed this feeling, but decided not to find out what it looks like at 6,000 feet.

Our dive mistress cultivated the friendship of many creatures by taking pieces of cut-up conch to attract them. A conch is the animal that lives in the horn like shaped sea shell. A French angel fish took pieces from her mouth (she removed her regulator); a golden tail moray came out of his lair and responded to pats on the head, of course the food helped.

We were treated to a night dive for our last dive experience of the week. My buddy and I weren't quite sure it was a treat, however, as we clutched each other tightly in the darkness, dive light not withstanding. In fact, my second night dive experience during my second week wasn't any more reassuring. Although I saw an octopus and some other interesting night creatures, I had my first (and hopefully last) experience of running out of air! With very little air in my tank I broke the surface, happy to have my head above water.