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How do the cameras used to film and photograph the deep sea withstand the pressure? (self.askscience)
submitted 3d ago by Mewnicorns
Title says it all.
SpeedyHAM79 86 points 3d ago
There are really two ways to do it-
1. House the camera in a vessel that withstands the pressure and has a clear viewing window for the camera, or-
2. Build the camera with non-pressure sensitive electronics and fill it with a non- conductive fluid (such as mineral oil) so that there are no internal pressure fluctuations that would damage the components as the pressure changes with depth.
Underwater cameras, as well as cameras used in outer space, have been built both ways.
1. House the camera in a vessel that withstands the pressure and has a clear viewing window for the camera, or-
2. Build the camera with non-pressure sensitive electronics and fill it with a non- conductive fluid (such as mineral oil) so that there are no internal pressure fluctuations that would damage the components as the pressure changes with depth.
Underwater cameras, as well as cameras used in outer space, have been built both ways.
[deleted] -1 points 3d ago
[deleted]
frigloo 7 points 3d ago
i'm struggling to imagine pressure sensitive batteries, capacitors, lenses... No air, no problem.
aries_burner_809 10 points 3d ago
Well, speedyHam didn’t word option 2 quite right. The fill fluid isn’t to prevent fluctuations, it’s to provide an incompressible fill of the camera interior so the seals between the water on the outside and the oil in the interior don’t blow in when the psi starts increasing. Air is compressible so the seals would deform inward. And at depth, the pressure could certainly affect some choices of camera part. Anything that is not solid metal or glass could have some deformation and could therefore crack, or behave differently.
colechristensen 8 points 3d ago
Not particularly, just don’t put in any air gaps.
Most materials just don’t care about the absolute pressure that you get all the way at the bottom of the ocean. It’s when they have to resist high pressure on one side and low at the other that’s the problem. Drop a chunk of glass into the Marianas trench and… nothing interesting happens. Same for plenty of materials.
Make sure nothing is holding on to a bubble of air and can survive just fine submerged in mineral oil and you’re good.
Most materials just don’t care about the absolute pressure that you get all the way at the bottom of the ocean. It’s when they have to resist high pressure on one side and low at the other that’s the problem. Drop a chunk of glass into the Marianas trench and… nothing interesting happens. Same for plenty of materials.
Make sure nothing is holding on to a bubble of air and can survive just fine submerged in mineral oil and you’re good.
Blakut 3 points 3d ago
I feel like a transistor/capacitor would be deformed or crushed by high pressure but I can't find anything as a source to back it up.
linkhyrule5 1 points 2d ago
IC transistors and capacitors are completely solid state, they're just blocks of material that are non-uniformly treated and doped. Mind you, capacitors are geometry and material dependent, so the increased pressure *might* directly affect the capacitance... but a printed capacitor is still not going to catastrophically implode or whatever.
Mewnicorns [OP] 1 points 2d ago
So I was asking this because I was reading about the submersible used in Blue Planet. It had a 7” thick acrylic dome where the passengers were seated, though it could only go down about 1,000m so not quite THAT deep. But they said it’s flexible and compresses without breaking, which surprised me since it’s just a big air bubble, but I guess at depths lower than 1,000m, it might stop compressing and begin to crack
With the cameras (and robotic arms they use to gather samples that need to be very precise), I’m surprised the resistance they face at that depth doesn’t seem to affect the maneuverability. You can feel the drag of the water even at much shallower depths. But i guess if fish are somehow able to swim at those depths, then there’s no reason a solid piece of metal couldn’t. No matter how much I try to wrap my head around this subject, I am never quite able to. Something always surprises me.
With the cameras (and robotic arms they use to gather samples that need to be very precise), I’m surprised the resistance they face at that depth doesn’t seem to affect the maneuverability. You can feel the drag of the water even at much shallower depths. But i guess if fish are somehow able to swim at those depths, then there’s no reason a solid piece of metal couldn’t. No matter how much I try to wrap my head around this subject, I am never quite able to. Something always surprises me.
colechristensen 1 points 2d ago
The water at the bottom of the ocean is only very slightly more dense than at the surface, water in general only compresses a tiny bit… to the extent that it had only negotiable effects on the performance of craft going through it.
_Oman 1 points 1d ago
My dive camera can go 10x deeper than I can. The outer case maintains 1atm for the camera itself. The smaller the vessel and the less air inside, the easier it is to engineer.
For "any depth" cameras, do you what the animals do... you don't have any air space. Liquids (for our purposes) don't compress. Solids don't care much about pressure, either.
For "any depth" cameras, do you what the animals do... you don't have any air space. Liquids (for our purposes) don't compress. Solids don't care much about pressure, either.
SilasCloud 8 points 3d ago
Apparently they’re housed in special structures that keep them at the same pressure as up on land.
“Conventional underwater cameras and their light sources are housed in pods that keep the contents dry and maintain interior pressures of about 1 atmosphere (.0.1 MPa).”
https://ntrs.nasa.gov/citations/20110016860
“Conventional underwater cameras and their light sources are housed in pods that keep the contents dry and maintain interior pressures of about 1 atmosphere (.0.1 MPa).”
https://ntrs.nasa.gov/citations/20110016860
coldbloodedking 1 points 3d ago
Deep-sea cameras are constructed using extremely durable and pressure-resistant materials. They are often made with high-grade metals like titanium or aluminum alloys that can withstand the immense pressure exerted by the water at great depths.
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