Ziploc - A housing manufacturer for the horrifically cheap?

[Sparhawk13401]

Ya - the "if" factor would seem to be the biggest problem.

I took two Ziplock bags down to 28' for a 35 min dive on the weekend. I put paper towels in them, so any leaking would be obvious, and they came out dry as a bone.

Now am I willing to bet my digital camera that the next bag won't leak as well...........I dunno.

 

[bleeb]

Like many here in past threads, I've always assumed that the camera structure itself wouldn't be too happy with the pressure force of the water on it, never mind water leakage. After all, 30' down, each side of the camera has to support an extra 10-100 lbf. But the overall unhappiness is all an assumption. Does anyone know for sure what will happen, possibly the hard way from, um, experience?

 

[ianw2]

Behold upon these favored citizens that it was found that they could place a cheap cereal box camera in the mask and then close the mask with a plastic bag affixed up under the chrome brass lens retaining ring thus rendering it suitable for great depths in yon pond or seabed.

Nemrod: I had a silicon bag that I did this with back in '74 when I was first certified. I used an old oval US Divers mask and my Kodak Brownie. I used a hole saw to cut a bigger disk to epoxy onto the film advance knob.

I actually managed to take some passable photos of my high school swim team from the bottom of the deep end.

Man...I'd forgot about that. Thanks for the reminder!

Ian

 

[Sideband]

Like many here in past threads, I've always assumed that the camera structure itself wouldn't be too happy with the pressure force of the water on it, never mind water leakage. After all, 30' down, each side of the camera has to support an extra 10-100 lbf. But the overall unhappiness is all an assumption. Does anyone know for sure what will happen, possibly the hard way from, um, experience?

Actually, I don't think that is true. My thinking is that would be true and there would be problems if the camera case were a solid, air tight container. Since there are gaps and holes in the case, the pressure is equal from all sides, including inside out. Comments?

 

[bleeb]

Actually, I don't think that is true. My thinking is that would be true and there would be problems if the camera case were a solid, air tight container. Since there are gaps and holes in the case, the pressure is equal from all sides, including inside out. Comments?

Just throwing ideas out, but consider the fact that your camera which is 6 cu. in. on the surface wants to be 3 cu. in. 30' down. And for the camera to stay 6 cu. in., its structure has to support those one or two hundred pounds of force.

Hm. Just had another thought. My hidden assumption was that the bag was squashed pretty flat against the sides of the camera on the surface, before sealing it up. If you were to blow it up like a balloon before sealing it, so that it started life as 12 cu. in., then maybe the sides of the camera wouldn't start to collapse until you got it below 34'...

Any more thoughts?

 

[miketsp]

Actually, I don't think that is true. My thinking is that would be true and there would be problems if the camera case were a solid, air tight container. Since there are gaps and holes in the case, the pressure is equal from all sides, including inside out. Comments?

Boyles Law still applies to the whole setup. At some point the bag internal volume will drop to equal the camera volume. After that the camera is sustaining all the pressure.

 

[Sideband]

Just throwing ideas out, but consider the fact that your camera which is 6 cu. in. on the surface wants to be 3 cu. in. 30' down. And for the camera to stay 6 cu. in., its structure has to support those one or two hundred pounds of force.

Hm. Just had another thought. My hidden assumption was that the bag was squashed pretty flat against the sides of the camera on the surface, before sealing it up. If you were to blow it up like a balloon before sealing it, so that it started life as 12 cu. in., then maybe the sides of the camera wouldn't start to collapse until you got it below 34'...

Any more thoughts?

That last thought was what I was getting at. You would have to maintain "excess" air in the bag or all of the buttons would be constantly pressed by the squeeze. As long as there is an air gap around the camera the camera itself is in no danger of crushing.

 

[DiverLS]

Another problem is the air between the lens and the bag. Since you can't "burp" it like other underwater lenses, you will be stick with that bubble in your pictures. The examples Blazinator show won't have that problem becaue the lens it in contact with the water but that sure looks complicated.

 

[Nemrod]

Nemrod: I had a silicon bag that I did this with back in '74 when I was first certified. I used an old oval US Divers mask and my Kodak Brownie. I used a hole saw to cut a bigger disk to epoxy onto the film advance knob.

I actually managed to take some passable photos of my high school swim team from the bottom of the deep end.

Man...I'd forgot about that. Thanks for the reminder!

Ian

Yes, I managed several pictures using a variety of inexpensive cameras down to depths maybe as deep as 30 feet or so, probably less. Someday I will look back into my vast picture archive (all film and slide) and see if I can find them.

N