Why aren't camera's buoyant by default?

[mrchen911 6]

I've had 3 DSLR cameras and Sea and Sea housings for them. On every single one, I've had to use floats on the arms to make them neutrally buoyant. Why aren't they designed as neutrally buoyant to start with?

[TimG 62]

Your experience is pretty much true of any DSLR and housing.

I guess to deliver a neutrally buoyant housing would mean either making a bigger housing using buoyant materials in addition to aluminium; or maybe some new material: carbon fibre? Titanium?  Which, I would guess, would be significantly more expensive.

A lot of the weight though can be strobes/batteries/lenses so you are pretty much always going to need additional buoyancy to get to close to neutral.

 

[Stoo 42]

Ya, I agree with Tim... I don't find the weight of my Aquatica system unmanageable, but I would mind if the thing was 20% bigger. Or 50% more expensive.

I've considered adding floats, but they're just more bulk to pack and I really don't need that.

[rwe 4]

Good question.

Small, negatively buoyant housings get a lot of positive press for this characteristic. Usually, they are described as being more ergonomic. However, IMO, adding all the floats required to make the housing, strobes, brackets, and arms close to neutrally buoyant make the system less ergonomic than a larger housing would be, both in and out of the water. If you are going to have to add positive buoyancy, why not put part of it in the housing and reduce the clutter/drag/expense/annoyance of all (or at least part of) the floats? And if you decide to not use strobes or lights, it would certainly be much easier/cheaper/ergonomic to add weight to a buoyant system than it is to add floats to a negative one.

[ChrisRoss 150]

Buoyancy requires volume, if you want it more buoyant it has to be bigger.  The other part of the equation is the port, dome ports being more buoyant, so you can't make the housing buoyant independent of the port.  The last issue is that the rig will be more stable if the buoyancy is located above the rig, so with the float arms above the housing it can effectively hang below them and won't try to twist around. 

To try to do it all the housing you need to take the volume inside the floats and add it to the housing and some extra volume to compensate having the extra metal to enclose that volume.  This means a bigger block of aluminium and more machining to remove the volume you have added so expense goes up.  I would argue if you have arms for strobes anyway the additional volume in the float arms won't add a huge amount to the drag.

[adamhanlon 0]

To answer why housings are not neutrally buoyant...

They sometimes are, but by the time you add a variety of different ports, lenses, strobes, lights and accessories, it becomes impossible for a "universally" neutrally buoyant housing. Of course we also dive in fresh and salt water, which varies the buoyancy characteristics too.

It is easier to add buoyancy to a housing than it is to add ballast.

I prefer a slightly negative housing to a buoyant one. If shooting video, the housing needs to be completely neutral and trimmed off level, which is one of the advantages of "proper" video housings over SLR ones for this purpose.

The general desire for smaller housings to allow for easier travel is somewhat of a red herring. Larger housings actually tend to have better buoyancy characteristics. For those of us the drag these big heavy things through airports, we are doing so in order to try and capture the best images possible. If a bigger housing has better handling and will make me more productive in the water, I will figure out the travel bit!

 

 

[rwe 4]

I agree with all Adam's comments except I do not understand why adding ballast would be more difficult than adding buoyancy if you actually ever needed ballast. You can buy lead sheets in multiple thicknesses which can be easily cut/bent/etc., or coated or uncoated lead fishing weights which would be easy to attach to arms or housing brackets. And with a density of 11.33 g/cm3 the volume of any lead ballast should be quite small compared to floats volumes.

[adamhanlon 0]

I'm not sure I want to travel with (or carry around) extra weight!

[TimG 62]

1 hour ago, adamhanlon said:

I'm not sure I want to travel with (or carry around) extra weight!

Amen

[phxazcraig 115]

Some are, and I've seen Canon supply weights for some of them.  (Point-n-shoot models back in the day, like the SD870is).

I was on a liveaboard in 2012 where a guy had a brand-new single-strobe Sea and Sea camera in a housing.  Near the end of the trip, he was climbing back aboard when he realized he'd unclipped the camera and somehow not handed it up.  Camera missing - boat goes into action.

Divemaster organized willing divers to jump back in and do a coordinated grid search. (Wonderful training.)  Groups of three covering one line with other groups of three covering the same ground at a 90 degree angle.   We searched extensively under the boat, but we found nothing.

On questioning the owner, he said he'd tested the camera initially in a sink, and it sunk.  However, that was in fresh water.   We figured that in salt water it was buoyant, and the whole time we were looking down at the bottom searching, it was drifting away on the surface.   $1000 loss, plus all his photos that week.

[mrchen911 6]

Ouch