Photo of the Week: November 16, 2009

Hi Gang!

Lucky me, I am still in Indonesia, but unfortunately I had to say goodbye to Captain Steve and wife Jan. They had to go back to Maui. Not exactly the end of the earth. The Captain will only be at home for a couple of days before he heads off to California to bring his newly purchased boat back to Maui to be re-outfitted. Frankly, I am not envious of that chore, but I do look forward to the long-range capabilities that the new boat will have for working divers.

In the meantime, lucky me, I got to keep diving in Indonesia. On the second day of diving after Captain Steve and Jan departed I found a pair of Coleman shrimp on a fire urchin while diving off Bali. Coleman shrimp are found exclusively on fire urchins. This species is often encountered in pairs, and that was the case on this dive. Usually there is one larger shrimp, the female, accompanied by a smaller male. No doubt, their striking pattern and vivid colors make these shrimp excellent subjects for macro photographers.

Of course, what is attractive to you and me might not be so highly thought of by the host fire urchin. The shrimp occupy a part of the test of the urchin where they have removed the tube feet and spines. Ouch! The shrimp are then free to move about on the sea urchin amongst the poisonous spines without any harm.

Female Coleman shrimp are approximately one-inch long. Even a single shrimp is large enough to fill a pleasing percentage of a frame with a lens that is well suited for macro photography, and with a pair of shrimp, filling the frame is even easier. I used a Nikon 60 mm lens behind a flat port in a Subal housing for this week’s POTW.

Capturing a good shot of Coleman requires paying special attention to the head, especially the eyes, claws and other body parts to make sure they are not blocked by an urchin spine or by the body of the other shrimp. Coleman shrimp often move about, so if a body part is blocked waiting a few moments will usually solve the problem.

Then there is the issue of getting a good exposure. I find many white subjects reflect a lot of light and are easy to over expose. Certainly that is the case with Coleman shrimp. I want to maximize my depth-of-field to get the bodies of both shrimp in sharp focus. That means closing down my aperture. But even with my aperture closed down, when shooting from close range Coleman shrimp are easy to over expose. I use the lowest ISO offered by my camera. With my Nikon D300’s that means ISO 200, and vary my strobe power and f/stop according to my histogram being very careful to make sure that I am not clipping, or over exposing, the white body parts.

I am not sure if Captain Steve was able to photograph a Coleman’s shrimp on a fire urchin before he had to head home, but I know that I did not get the chance until the second of my back-to-back trips. Perhaps this shot will encourage the Captain to put together another trip to Indonesia in the near future. If he does, I hope you can come along.

I also hope you enjoy the week!
Marty