Eric, I checked out your '03 shark trip galleries yesterday. Stunning stuff. The Mokarron hammerhead shots are particularly impressive. I also enjoyed seeing the people pix - especially because I know the Brit subject matter.
I agree with Ryan that the D100 shots are nice, but I disagree with Ryan about the sunrays. As a D100 owner I am worried by how poorly the camera has dealt with the sun, producing large white sunbursts/sun spots (both in my own tests and in Mauricio's pix). I do realise that the medusae were shot in shallow water, which always makes it difficult to keep the sun spot small (because you are closer to the surface). A smaller aperture would also have helped to make the sun smaller (the info does not say what aperture was used) plus possibly a slight underexposure of the background.
I am sure that in Berkley White's D100 article at Backscatter.com he had some sun burst shots with better results - but I can't find them now.
But I am concerned that this is a difference between film and CCD - in they way that each respond to the massive overexposure caused by including the sun in a scene.
I do think that sun spot size is also a result of the 1.5 times reduction in lens coverage with the smaller (than film) chips in the D1, D100 and S2. This means that the sun will always be bigger in the frame for any given lens that it would be on 35mm film.
I guess I will know the answer to all this when I finally get my D100 into tropical water (Grand Cayman) in April and can see how it performs with shots I have taken many times on film.
My tests with backgrounds in UK have been inconclusive (see image below). Viz has been about 1 metre so I have had to do everything just below the surface. This shot below is the full image taken with D100 and 16mm at about 1 foot (30cm) below the surface (f14 @ 1/1/250th - no exposure compensation Aperture Priority - Matrix metering). I think that the sun spot is reasonably controlled here - but I still find it a bit large and unsightly. I think that I have got away with it to some extent because part of the sun is obscured by the edge of Snell's window.
I am interested to hear how others have been getting on with sun bursts? Looking through various people's online galleries shots with the sun in are quite rare.