Over-under shooting with a big dome

Any tips there?  I've tried a couple of times, and the problem I have is that the rig is too heavy to lift halfway out of the water and compose.  I sort of shove it up pointed in a general location, shoot and hope for the best.

This is what I'm trying to use, with the addition of two strobes, two arms and a focus light added on.   It may be neutral in the water, but it's about 30 pounds out of it.

I'm thinking a float is the only answer.  I tried (briefly) in Roatan this year of trying to stand in a shallow area with the strobes hanging down in front, lighting the foreground.   The idea was to get a sunset shot of the Reef House with their 'pool' area lit up.  It failed for several reasons, but the main one was surf shoving me around.  And even standing this was a tough hold.

It's got to be at least partly inflatable, so I can get the ideal buoyancy.  Hmm.  Off to the DIY forum!

Maybe put one of those kids' arm floats around the port barrel and inflate/deflate as needed?

I like that idea - floaties!

I also thought of some sort of stick to go from my belt to bottom of lens.   Transfer the weight to me, and I balance with the BCD inflation.

I have an 8" dome, and I use floats to give my gear positive buoyancy. The problems i have are:

• focus... need a huge depth of field to keep both over and under in focus, due to the optical characteristics of water (refraction index).
• size difference: water magnifies. If i have a model half way under, half way above, her legs will appear disproportionately large compared to her body. Not exactly elegant. 

I will follow this thread with attention. Ned

ON my last dive trip (first with new Nauticam D850 housing) I didn't even get to try an over/under shot.  I still haven't come up with a float system.  Would love to see a shot of yours.

How much different is the magnification above and below water with a dome port?  I thought it eliminated the magnification effect.

As for depth of field, I suppose I'll just have to shoot at F8-F16 and raise ISO.

Just a quick snapshot to show the difference in magnification despite the 8" dome by ikelite

If it weighs 30 lbs and neutral in water, it has a volume of about 1/2 cu ft. To hold neutral half in-half out, 1/4 cu ft. would be submerged; and 1/4 cu ft. of near weightless material would have to be placed underneath. 1/4 cu ft could be made up with a piece of foam or inflatable bag, 4x9x12 in. Would probably be best to make the 4 in dimension its depth and the 12 in. dimension parallel to the long axis of the housing.

To make it stable in water, you could eliminate the lights and tray, and attach a thin plastic platform to the bottom of the housing using the tapped holes where the tray normally fits. Then bungee the foam piece or bag underneath it.

I like the bungee idea and the inflatable float idea.  (Seems like someone should already be offering such a product).

I'm not keen on removing the lights at all, for two reasons.

First, I don't do over-under shots exclusively.   This is just something I'd like to do at the start and end of a dive, and I need the strobes the rest of the time.

Second, I want to illuminate the under portion with dual strobes hanging down.

I like the idea of the inflatable float because I could carry it through the dive without it affecting me, then inflate/deflate when necessary.

Does everyone doing over/unders with these big rigs use floats?  It would seem a requirement.

PHXAZCRAIG wrote:

I like the bungee idea and the inflatable float idea. (Seems like someone should already be offering such a product).

Hi Craig,

I bought this float, but still have to test it out for split shots: https://www.amazon.de/gp/product/B078YJWSGV/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

These floats are inflatable collars for pets, but this one fits nicely around my Nauticam 140mm/N120 and the Zen DP-170-N120 domes. I expect it to work nicely...

Wolfgang