Cave recording

[Justin Deming]

Let me know what you think of this idea. I hope this is the right forum for this.

A bit about me, I am new to the Videographer business, but not new to video cameras. I can't even attempt this for about 6 months.

I want to take my camera into a certain cave and record the wonders of the underground formations. This certain cave is fairly popular, but what most visitors don't know, is that in adition to the 3 miles of well known cave, there are another 9 miles of cave that can only be accessed by diving under a small wall. I would like to show how the public has ruined the well known parts of the cave by spray painting all over it, then show the natural beauty of the un spoiled parts. My video will not reveal the location or name of this cave, because I do not want people learning how to access and ruin the secret part of the cave.

It is not the type of cave where you pay to get tours, it is in a national forrest, and there is really no control over it at all. A friend originally invited me to go explore it with him, and we drove about 10 hours to get to it. This place is just amazing, and since I went there, I have always wanted to go back and record it. I have never seen the secret part. Our plan was to dive inder the wall when we went, but the person with the wetsuits did not show up, and only one of us went under the wall to verify that the rumor of the secret part was true.

Anyway, I need a bit of guidance about how to get good footage. By the time I go to do this I will have a JVC GY-HD100U camera, and at least 1 led panel from lite panels. I plan to have at least 4 people on this trip, so that once we go into the secret area, each night 2 people can leave the cave to recharge batteries, and the other 2 can stay with our equipment.

What can I use to keep the camara safe while bringing it under the wall? I don't need to keep it rolling while the camera comes through, it just has to be dry, and safe from bumps.

How many batteries do you think you would need for 8-10 hours of operation?

And the biggest thing, how do you get good enough light? Everyone will have bright LED headlamps, and the camera will have a spot lite panel mounted on it. Will this be enough? I can bring more lights if needed, but lite panels cost about a thousand dollars each, and I also have to own, charge, and haul enough batteries to lite the palce up.

Also, does my camera need protection from water? One section I know of has a really nice waterfall. I can keep the camera mostly out of the water, but it will end up getting some spray on it for sure.

[Dean Sensui]

Justin....

When you dive to access the other part of the cave, how deep are you going to go?

A Pelican case won't be watertight at depth, so you will need a case that can take the pressure of your dive, and possibly more.

As for lights, the UK Light Cannon is a possibility. Very bright HID light. Princeton Tec makes an LED light that's supposedly bright, too. For the amount you'd spend on LED light panels you can get several of the above lights and really cover the area. Perhaps diffuse some of them and use others as highlight spots. Really depends on how big the cave is and how you want to light it up.

Perhaps do some tests in an equivalent space before heading out. An advantage of using dive lights: you don't have to make a housing to transport 'em. But you'll need to find efficient diffusers that can spread out the beam without too much loss of illumination.

Most of all, make sure all the lights match as closely as possible. You won't want a mismatch of color temp and spectral distribution especially in a situation where the natural color of your surroundings will be so important.

Good luck. It sounds like a magnificent project. Such a shame that there are so many out there who don't respect natural wonders and feel compelled to deface them just to leave their mark.

[Justin Deming]

Dean, thanks for being so supportive.

The dive is only 10-12 feet deep. I looked at pelican cases, but they claim to be able to float with up to 150 lbs in them (depending on the size of case of course). I can't have it floating, because I have to get it under the wall. I hear cases do exist that have the capability to pump the air out of them. I am hoping someone knows about these cases.

Thanks for the info on the dive lights, that could really help me. I might not have thought about matching color temp on all the lights, that really makes sense.

I'm off to read about those lights you suggested.

[Chris C. Corfield]

I will second the UK HID Light Canon suggestion. They are very bright and light to a daylight colour. Each unit comes with two diffuser disks that are inserted into the light housing. As for a case let us know what you find.

Chris

[Meryem Ersoz]

since you're only diving 10-12 feet, you could consider a splash bag instead of a plastic underwater housing or pelican case, which are rated to twenty feet. the advantage to a splash bag is that you can use it to protect your camera while you're in the cave as well. ewa-marine makes them. i have one for a GL2 (which is my home movie cam, not my best cam), and i used mine at the beach to protect from salt, spray, and sand. there are some disadvantages (vignetting/irising), but you save a lot of price. if you do a search here on underwater housings, you should be able to get more substantial info on the various options.

[Dean Sensui]

Justin...

Just for quick calculations regarding buoyancy, figure on 64 pounds of ballast for every cubic foot of volume in fresh water.

I'm not sure how well bags would hold up even under the modest pressure found at 12 feet (which comes to 6.5 pounds per square inch). Water has a way of finding really small pinholes under the slightest amount of pressure.

Also, when you add up the number of square inches over a camera's surface, that's a lot of pounds of force that would be exerted upon the camera's exterior if the camera's in a soft-sided bag.

If it were my own camera I'd see if I can find some sort of protective cylinder with a stout neoprene o-ring, and a cap that's locked with snaps such as those found on Ikelite U/W housings.

You might be able to fabricate something out of PVC pipe and plexiglas.

My concerns about the bag is just conjecture. Nothing like doing an actual test (with a disposable mockup) to see if it'll work or not.

Good luck!

[Meryem Ersoz]

dean's definitely the expert on this one. you should listen to what he says. i've only ever used mine for surface snorkeling. it does provide great protection against the elements, however, so if you're worried about other environmental impacts, it's way better than a raincover....

sounds like a really fun project, good luck....

[Jim Michael]

How large are the chambers you intend to illuminate? Are you just going to generally shoot at close distances or try to get an entire large chamber in the shots? Knowing this would help determine the amount of light you'll need. If you take a still camera with a wide angle lens you could paint the chamber with light during a time exposure.

[Justin Deming]

Dean, I think you are rigt about bags, I'd be afraid to take it that deep in a bag. I like the PVC tube idea. Whatever solution I choose, I will definately test it with some sort of dummy before risking my camera.

As for the size, some parts are smallish tunnels, and in other areas it can open up to very large chambers. The largest chamber I have seen so far had a ceiling about 50 feet high, and was similar in distance from one end to the other. Of course, we are talking about extremely irregular shapes. This place is so irregularly shaped that we once spent about an hour in a chamber, knowing that the way out was somewhere in there before someone climbed to where he could see the exit.

I looked into the UK HID light, and I agree it seems to be a great light. They are much less expensive than lite panels too. I can buy 5 UK HID's for the price of one Lite panel. I'm thinking I'll get at least one for each person in the expedition, plus a few more just for lighting up the bigger rooms. Ultralight Control systems has a system I can use to mount one to my camera base plate. They also have a cool little joint that can be set up like a tripod, it would be perfect with a light attached to it for placing and aiming the light. What I need really is maximum flexibility, because planning shots in advance cannot be done, and these seem perfect. 450 battery powered lumens each! That is so much better than any other portable light out there.

I will definately bring a camera for stills, and incrporate those into the presentation. The video is key though, it's just so hard to get perspectve from a still in such a place.

You guys have helped allot, I think all i need to figure out now is what to wear, and what to eat!

I'll keep you posted when I find a safe waterproof housing. I'm waiting for Pelican to respond about wether they can make one of their cases do this job.

[Dean Sensui]

Justin...

The only problem with the UK Light Cannon is that it sucks down batteries real fast. I have one and, using 5 amp-hour NiMH batteries, it runs about an hour.

It might run longer with alkaline batteries, but I haven't tested it. Of course, there's no reason why you can't bring extra batteries except one:

It might run a little hot, depending on the environment. Not halogen-hot, but warm enough to possibly make it run at lower power on its own. It has its own protective circuitry to prevent it from cooking itself.

You might want to also check out the Princeton Tec lights. It's probably not as bright as the UK. But it will probably run longer and cooler.

I don't know what the spectral distribution is on those lights, whether it has a broad spectrum or narrow. But if you can find a local dealer you can easily do a test with a camera.

Great idea to bring in a still camera to provide additional documentation. If nothing else, it'll provide production stills for publicity.

Also, it might be helpful to start seeing if you can actually sell this footage somehow. Either a documentary group, network, etc. Definitely keep the location a secret so they can't poach on your work.

As for what to wear, I'm a firm believer in layered polypropylene. Works even if its wet. Keep in mind that about 40% of your heat gets lost from your head and neck so a balaclava is helpful. If it's too much then it can be rolled up into a crew cap. Better to be slightly overdressed than underdressed. Hypothermia can get you even if it's just 75 deg. F.

And as for food, depends on how spartan you want to be. I did the 200-mile Seattle-Portland bike ride (two days) and lived off Power Bars and Gatorade. Of course for the overnight stay a good friend made some killer pasta dish!
Regarding the Pelican case at depth: The main concern I'd have is the closed-cell gasket they use. If it were a solid silicone or Neoprene o-ring I would be a lot more confident. I'm fairly certain the case can take the pressure. After all, an adult can stand on it without crushing it.

Otherwise, Pelican cases really do work. I swam ashore on a few assignments with one and had no problems whatsoever. And I use one on my boat to keep dry stuff dry.

[Stephen Finton]

Bring a wide angle adapter, too! Maybe even a fisheye.

[John Kang]

To my understanding, cave exploring and underwater scuba diving are dangerous activities.

I understand you'll have a team going, but it might still be a good idea to set something up as an emergency plan. Just in case.

Contact time to reach someone not located at the cave like some family member. If they don't get a call, they call authorities who can rescue you.
Of course, they should have a map of the location and a plan on what you are doing. If you are going further into the cave, how will they find you, any marking on the walls, etc...

You might also want to carry some emergency packs with you. Blankets, medical items, like band-aids, etc...

I can't wait to see some of the footage you will produce.

One other thing, I know you wish to keep the location a secret, but will you be breaking any laws by going to the caves or filming at the location, are you tresspassing? While you might be in a public park, some areas may be off limits for safety reasons. Things to concider.

[Justin Deming]

Dean, I read a review of the light using alkaline batteries, and they claimed it lasted them about 4 hours before beginning to dim. I think it's time to buy one & test it. I hope the heat issue isn't a big problem. The cave is cool, but since this light is primarily designed for underwater use, the heat protection circuit could come into play. I could work arount that if I have to by dipping the lights in the nearly freezing temperature water to cool them off as needed.

I looked at the princeton tec lights, and their best was about 120 lumens, not near the 450 lumens this puts out.

Food and clothing should be pretty easy, there is a river, so al I need for water is to bring my filter along. I'm in the Army, and grew up as a boy scout, I can supply us with MRE's, or be more creative. Powdered gatorade is deffinately coming along.

As for selling this, I really have no idea how to do it. This will be my first attempt to sell any of my work. Up to now I have done all my work for fun. It's not my first adventure into business, just my first time in the film business.

John, your concern for safety is understandable. I am a certified combat lifesaver. That's not a medic, but enough training to stop major bleeding, give IV's, splint broken bones etc. We will definately be taking a medical kit with us just in case. As for rescue, as a precaution I will take the let someone know advice, but that's one reason for the team of at least 4. If someone gets hurt, there is someone to stay with him, and 2 to go get help. Also, this is not my first time in a cave, plus 2 of the people going have been in this cave more than one time.

I will definately check with the local authorities about any restrictions about filming, but I'm pretty sure there is no regulation at all of this place.