Does rig buoyancy affect camera shake?

In your opinion does the buoyancy (+/-) of your rig affect your footage? Is it easier to capture steady footage with a heavier rig? If you hold a feather in one hand and a brick in the other, which one stays more stable over 90 seconds?

My wife has a new dSLR housing that is ridiculously heavy UW; I have been going through the steps to adjust the buoyancy of her rig and my mind starting wandering into video land. With a still camera it seems to make all the sense, the flash is going to freeze any motion you have anyway so why not have a near neutral rig. But I am not sure it translates to video. Opinions?

Ryan

In my opinion, rig buoyancy has a bigtime affect on camera shake. Even more so for video since you are recording 10 seconds plus per shot.

If your housing only has a viewfinder, your typical shooting position is housing held up to your face. If your rig is very negative, that will push you head downward. Head downward is usually not a great postion to shoot video. Using your fins or body to combat the head downward position will create shaky video.

In my opinion, rig buoyancy has a bigtime affect on camera shake. Even more so for video since you are recording 10 seconds plus per shot.

 

If your housing only has a viewfinder, your typical shooting position is housing held up to your face. If your rig is very negative, that will push you head downward. Head downward is usually not a great postion to shoot video. Using your fins or body to combat the head downward position will create shaky video.

I agree, the problem with the buoyancy is the fact that we are shooting extended periods of time, it is a non question for still camera's. I also like your point about having to combat the weight. However, take it down a notch on the weight side; what is easier to hold steady for 10 seconds, a perfectly neutral housing or one that has ~some weight to it? Since most manufacturers of housing try to make them slightly negative I am guessing they believe that is preferred, but is it? Or does it just come down to skill

I'm just a hobbyist, and I only dive 2-3 trips a year, so my opinions are from my very limited experiences.

If I have to position the camcorder and or my body in some kind of weird position, I prefer my rig to be perfectly neutral. Otherwise, slightly negative works well for me. I have a top mounted monitor that can be tilted and rotated. With my rig, the best position for me in an open water situation is holding it slightly below me with the monitor tilted up.

For macro shots with zoom, the only way I can get decent footage is to rest the camcorder on the bottom or on something solid. In this case, a very negative rig works well. I will carry an extra 2lb weight and place it on top of my housing in cases like this.

The more experienced guys probably have their own methods and are definitely more skilled than I am.

This is just what I do.

Slightly negative seems to be best. Too negative will be tiring. But a positively buoyant housing will be awkward. (If you clip it to your chest, you don't want it floating up and banging you in the nose).

For "shy creature" footage (e.g. some gobies), I like to place the camera down pointing in the right direction, then swim away a few meters so that they resume their natural behaviour. For this, the housing needs to be negative.

Adding an external monitor on a adjustable mount means you can position your head and body comfortably for most shots.

Another important factor is the buoyancy balance. I had one housing that was "nose heavy". Until I got it balanced (by moving the battery pods backwards), it put a strain on the wrist while shooting. Any strain will, sooner or later, translate to shaky footage.

Regards

Peter

But a positively buoyant housing will be awkward. (If you clip it to your chest, you don't want it floating up and banging you in the nose).

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Any strain will, sooner or later, translate to shaky footage.

First of all, awkward when you're not shooting isn't really the key issue here. A tripod is awkward when not shooting, but if I need tripod, I'll use a tripod.

The question is what buoyancy factors help keeping the camera steady while shooting. I'd say that if buoyancy is the only tool you have for adding stability, then make the camera either rather positive or rather negative, depending on your situation. That's like using a chainpod on land -- not the best of all possible worlds, but if it's all you've got, it can be better than nothing.

But in addition to buoyancy, mass is important too. If your camera rig is perfectly neutrally buoyant, but has a mass of 500 kilograms, it will be pretty stable underwater -- you won't have to worry about hand-held camera shake. But no matter if it is positive, neutral, or negative, if it has a mass of only 1 kg, it will be difficult to keep stable.

Mass and shape are the main functions of stability. You will find that the bigger housings are more stable due to the size and mass. Shape also helps as well as where the grips are placed. A tube tends to spin easier than a box, even in water. Note how most of the tube designs have "wings" to stabilize the housings.

The other function is the diver. Doesn't matter how neutral or stable your housing is if you aren't. The best arrangement is a VERY slightly negative housing for mid water use. I normally put an emergency removable weight on the housing incase I need to let go of it. I pull the weight off and it floats up to the surface.

Others have talked about how important mass is...enough said. Now how I feel about +=- buoyancy.

Placing that housing in the sand in front of the eel hole or other mysterious critter and moving away isn't possible if the housing is positive. Near neutral also creates movement from any surge in shallower waters with the housing in the sand. I think the housing should be slightly negative but get the weight close to the handles if possible so torque is minimized. (in complete agreement with perterbkk)

I also cradle the housing, at times, in my open hands or with one hand so I can move the camera away from my face while recording. I do this to watch the lens from bumping the coral or critter and to distract the critter from the big eyeball coming to eat it. I couldn't do this move if the housing were positive or neutral.

I had to drop my rig once on a wreck to attend to a panicked diver. Although, I have to admit I gave the decision a second thought, I was glad it was negative, I knew where it was, and I could recover it on the next dive.

All that said, I sure wish my housing would bob on the surface if I ever let it go or got washed off a boat. With the new $$$ rig, I was thinking of ways to make it more buoyant on the surface or dive platform. Maybe a block of neoprene that would loose bouyancy with depth. Maybe a pop bottle clipped on it while on the boat. Still working on it. Just something to give me some more peace of mind since H20 insurance doesn't cover such mishaps.

Mark

All the housings I have owned and continue to own: VX1E in Ikelite, VX1000 in Sealux, Z1 in Gates and my new RED One in ............................ (under construction awaiting tests), have all been very slightly negative. If I need free hands I prefer it hangs from my BCD rather than float to awaiting boat propellers. I ALWAYS use a sturdy safety lanyard. If I'm in trouble I will always do what I can to send the cam to the surface so the footage can be used etc. I have a small SMB in my BCD for that very use.

Cheers,

Mark.