Yep, Hot tub....
My wife took this and mentioned something about evidence to use at the hearing. The good news is the new Nauticam rig has been underwater (a nice toasty 102 degrees F) if not officially baptized in saltwater yet.
The great news is no red lights or large bubbles.
This is the Zen 100mm setup on the Nauticam 7D with electrically fired YS-250's. I put one of those fuzzy car wash mitts in the spa to play with strobe position. I thought the long yarns would sort of replicate anemone arms or I could at least see some shadows to understand how the light was acting. I shot everything at 10mm, zoom ring is back ordered.
I quickly understood what you were trying to tell me about getting close enough to light the front of the subject. My normal macro strobe position started to go bad with the subject about 6 in. away. After some trial and error I was able to work out a couple positions that allowed me to get a reasonable exposure with the subject actually touching the dome. You can tell from the shot above that it was a very bright day in Arizona today. Ambient exposure was about f/8.0 at 1/250 Iso 100. So I was shooting my mini test, manual f/14 at 1/250 with the strobes around 1/4 power, diffusers on. I was playing with strobe angle, position for and aft, up and down, and power. Four variables will keep you in the water a while. I started off shooting my 13" x 19" lens chart and you can really see how the corners roll away optically. It's pretty clear why you can lose corner sharpness as you open up the lens. You can also see how the normal strobe position would cause problems. It's made worse by the reflective plastic but you get the idea. This is at 10mm f/14 1/250 about 1/4 power on both strobes.
This is the mitt I used about six inches from the dome. The shadow on the right is all from the sun.
Here is a shot with the fuzzy things touching the dome with the strobes positioned beside and behind the dome, angled in toward the subject, right strobe higher than left, 1 notch under 1/4 power.
After a little practice I think the issue is not so much the size of the strobe as it is how sensitive a great exposure is going to be to position and angle. Very minor changes give very different results. The good news is after playing around I'm confident I can get reasonable results with the big YS 250's.
The Nauticam is really feeling nice, everything comes to hand almost instinctively. It loaded up without a problem. I don't have a manual yet so I just screwed on the tray, stuck it in the housing and everything worked. My old S&S ports with Nauticam adapter ring look like they were made for it. If you look close at the top shot you can see I have both the handle and housing arm balls mounted so I could try out different arm mounting positions. I definitely prefer the arms mounted on the housing. I also figured out that when I'm doing this type shot for real I'll only need to use the shorter 5 in arm on each side. Unless I trying to use Martin's inward lighting technique, but that's for next time. I feel a good hot soak coming on.
Happiness is a new rig, a dry camera, warm water and more to learn.