Underwater filming?

IMO a "homemade" underwater housing is probably a bad idea.

Check at:

http://www.bonicadive.com/

http://www.ikelite.com/

http://www.ewamarine.com/

http://www.canon.com/

That's A Disaster Waiting To Happen

And I Can't Find One On

http://www.amazon.com/

So, perhaps, you should just get another camera, which is waterproof, and you don't need an extra case. Try this camera, from Olympus:

http://www.amazon.com/Olympus-Stylus-Digital-Camer...

That's The Olympus Stylus 850SW

I think it best if you bite the bullet and buy a purpose made case, it could work out cheaper than replacing your camera if your home made one leaks.

if it leaks your cam wont film anything, there is most likely a case you can buy for your cam, later consider light or lights

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