Making your own underwater housing

[Adrian]

I have an Oly Camdia 2500L, a nice 2.5 megapixel camera and I'd like to make a simple housing for it. Here in Spain the only housing available is a soft one, that retails for about 175 euros :naughty No way i'm going to spend that. I'm sure I can fix something up.

Any ideas? I have lots of tools available.

Adrian

 

[Pezman]

Good application for old regulator

One idea that I had was to use an old regulator and a heavy vinyl bag.

Put a glass-plate on the front of the bag. If you are handy, you can glue some heavy-duty rubber gloves into the side of the bag (these will let you manipulate the controls).

The reg is fastened to the botttom of the bag and attached to a little pony bottle. When you go down, the bag collapses, a partial vaccuum is formed and the reg lets air in. When you rise, a the bag wsels a little and the reg lets the air out. The compressed air will be very dry, so there won't be much problem with condensation on the lens.

The setup does not need to be very strong, since the pressure differential across the membrane is minimal (actually, this depends on how sensitive the reg is to some extent). THis makes it a lot simpler to construct.

The setup is essentially universal (i.e. it could hold a video camera as easily as a regular camera).

Buying the necessary parts might be a little expensive, but a lot of us have old bottles, regs etc. lying around unused.

 

[Adrian]

Pezman,
Thanks. I had an idea I saw many years ago on the same lines, using one of those old oval masks with a metal rim securing the glass to the rubber part of the mask, ie, using the faceplate of the mask as a visor and slipping a plastic bag under the metal rim, afterwards tightening it up. I would probably only take it down to 5 or so meters as I don't want to risk any leaks.

It turns out some friends left their regulator - a very simple one - here and don't need it any more.

Would the expansion and compression of air in the bag be important at these depths? I'll obviously test it before!


Adrian

 

[Pezman]

When you do the math, you quickly realize the effects of pressure! If you are going to stay above 5 meters, then you will be safe if the bag has 33% more air in it than the volume of air within the camera. If you are above 10m, then you need 100% more and so on. Estimating the air in the camera may be difficult, but it is certainly less than the volume of the camera itself.

The beauty of the compensated bag is that it is constant volume and the device can go to pretty impressive depths. I was designing a rigid case a while back and realized that the net pressure on the housing at 100' is 45psi. At that point, I decided to buy a case (this particular case has a 24sq" back, so it is opposing a force of over 1000 lbs).

At any rate, as long as the camera is relatively small, the changing volume of the bag won't cause enough of a change in buoyancy to bother you, so an oversized bag is probably just fine for the depths that you are talking about.

One thing that you might want to check out is whether the camera has any enclosed air-spaces in it, in which case the increase in ambient air-pressure might cause problems (e.g. the LCD display might have problems). This consideration would apply whether you are using the "oversized-bag" technique or the regulator technique.

Good luck and if you build this thing, please post pictures (of the device and the stuff that you photograph with it)!