UNDERWATER FILMING>

[Peg Leg]

I watched a segment on the Discovery channel last night.
It showed how this construction crew built a clear plastic box that was sealable to house a underwater camera. The water they were trying to film bedrock through was pitch dark and the camera could not film through this mess.
They had to take a look at the bedrock to see if it had any cracks.
The clear plastic container held about 10 gallons of clear water. They inserted the camera into this clear water and sealed it up. They lowered this box into the murkey water. It was able to ge a clear shot of the bedrock.
I do not understand how this was done because if the water on the outside of the box was to murky to see anything how was the camera able to pick up clear pictures from inside the box.
This would work for me perfect.
Can someone explain?
Thanks
Peg Leg

[ScubaFinder]

The clear water housings allow the camera to focus properly...when there is silt right in front of the focus mechanism it just scans back and forth through it's focal range. If you put 6-8" of clear water in front of it, it can lock a focus on the front glass, and then pick out details from there, even if they are in very murky water. It's not a "fix-all", but it does help the camera focus in bad conditions.

Jason

[Peg Leg]

Thanks Jason,
I think I will give it a try.
I have plenty of clear plastic sheets to work with.
Peg Leg

[Cablava]

Peg

Try using a clear plastic bag full of clear water, with the camera lens pressed hard to the bag and the bag pressed hard against the subject. Its how we took film of the port lock gate hinges in black water back in the early 70's cheap and easy, although the bag can be a handfull to deal with if its a big one.

Works with the mask pressed against the bag so you can select what you are going to film.

[mad4wrecks]

Peg, if you were listening to Bob Marx the other night, he described how the National Geo photographers did the exact same thing at Port Royal. They built a huge plexiglass aquarium, filled in with clear water, sunk it on the site, and had the divers press up against one side of it while they photographed from the other side.

Cool trick, eh?

[Dinkydick]

Where have you people been?

I was using this technique back in the early 1960's. Works good but has
a lot of set up requirements. Last time I use it was two weeks ago on a
US Navy ship to take digital photos of underwater damage to the running
gear.

The major problem with this approach to underwater photgraphing or video
is that it is a contact device and will only work best when in direct contact
with the items you wish to photograph.

Dinkydick

PS see you all in one week. That photo that Seahunter put in todays postings
is a Miller Dunn shallow water dive helmet. I had a similar one made by Morris
which had a kidney shaped port which caused a lot of distortion when looking
thru it. See you'all soon.

[mad4wrecks]

I posted that picture of my old friend, the late Art McKee, the grandfather of treasure diving.

Tom

[Peg Leg]

When I saw what they were doing with the plastic box the camera was not in contact with the plastic and the object they were filming was about a foot away. Maybe it was the camera they were using. They had to take a good look at the rock structure on the botton to see if it had any cracks. They were going to pour concrete for Bridge pilings and had to make sure it would be safe. The Bridge span was a whole section of bridge that was being brought in by badge so there could not be any cracks in the baserock or the bridge would fall.
I guess that when you have millions and millions available it does not matter what the camera cost but it sure does to me.
Thanks
Peg Leg

[FISHEYE]

I have a camera and scuba mask ad on to see thru murky and silty water.cant discuss it here.its pat pending.

[Peg Leg]

Fisheye,
Being somewhat of an inventor myself I think I know what you are designing and I think it will be easy to manufacture and not very expensive.
Good Luck
Peg Leg

[Cablava]

You could intergrate the two methoids and make a box leaving one side off and fit a clear soft membrane on the last side so you couls achive the shape of whatever you are trying to see. a couple of valves to fill the the thing with clear water and let air in when you are emptying the box.

Just an idea

[Peg Leg]

What if you made something that operates like a human eye but without any peripheral vision.
All it had to be is 2" long filled with clear water. In fact I do not think you would even have to use water. How about 2" of a clear substance attached to the lense.
I recalled when lasers were being developed they used a Ruby, now they use a Jello like substance and it works great.
I would also suggest that you design a TUBE with black sides so the when the lights on on there will be no glare from the sides.
I am expecting my UW camera in a few weeks then it will be Play time.
Later
Peg Leg

[pepper]

Ultimately, if I understand the concept correctly, what you need is a clear water
recirculation system to clear the water in front of the lense from upper water
levels to the lower levels and then incorporate your eye view of the lower water
level within the draft or flow of the upper level of clear water circulation.

Once again, I suggest a dual concept device. This device could be derived from
your 2" long filled with clear water (or other source) and an assistant *buddy* tube
that clears way for the optics with clear water from the top or another source for the
duration of time it requires you to investigate what you need.

Just some thoughts...

Best of everything.

Pepper

[Peg Leg]

Pepper,
Man you lost me.
I think that I will stick with a MD and if I get a hit I will just scoop up what is there and take a look in the sunlight.
You sure can't beat that.
I am making such a scoop and almost have it completed.
This sure beats refilling the Gulf of Mexico with fresh water (hahaha)
Peg Leg