underwater at night....shooting video without light.... Infrared.

I am not a scientist, so take this for what it is worth. Water filters out the visible red spectrum. I suspect it does the same with the infra red. Meaning your subjects should all come out looking black, I believe, if the only thing you are letting through the lens is the infrared spectrum. That might be different if you were using an infrared light to light up the subject. In which case I haven't a clue what it would look like.

Hey guys,

I'm very new here and very amazed at the great community that exists. Having said that im sadly not even a scuba diver but trying to get some information and research done regarding underwater video for a friend..... Has anyone here shot underwater video at night using only infrared or nightshot on some cameras? We're looking to do this possibly using a sony fx7 which is a 3 chip cam that does have a nightshot feature on it... Trying to find out if this in fact actually works or not or if you need to add additional infrared lights onto the housing, etc in order to even get some visuals..... ive searched all over the web and have been having many issues finding information so i joined this forum hoping some generous soul could help me out.

So does anybody know anything about this sorta thing or at least can anyone point me in the right direction?

All the best,

Johnny

Will the infrared on the camera see out of the housing ? Will it reflect back from the port ? Have you tried it topside inside your house looking outside through a window ? I suspect it will perform similarly UW.

I haven't tried it with my camcorder, but I know my infrared security camera reflects back.

Hi Guys,

I have an Sony HDR-FX7E and it does NOT have a nightshot feature. Perhaps the non European version (FX7) is different. I have a Sony 330E (DV) which does have a nightshot feature, but the infrared port does not "look out" of the Sea and Sea housing as it is placed well below the lens.

Roger

I'm not confident that anything which relies on Near IR will work very well underwater. Penetration the of non-visible EM spectrum is generally very low. This is true on both ends of the spectrum. To give you an indication, the extinction coefficient for light at 600nm (red) through pure water is ~ 9 x 10e-4 (OD/cm). At 1000nm (near IR) it is ~1.7 x 10e-1... nearly three orders of magnitude more opaque.

At work we use near IR lasers for remote sensing and when we fly over water bodies it manifests as a complete loss of all returns. Systems that are designed for bathymetric surveys (shoals) use blue lasers as that wavelength gives maximum penetration.

Cheers,

Mike

thanks guys for all your replies! i think i am just gonna have to test it out in a pool.... the mention of the housing possibly blocking the ir light though makes a great point! i may have to buy some extra ir lights and somehow makes them submersible and strap them to the housing to see.

any other thoughts/ideas?

thank you all i truly appreciate it!

thanks guys for all your replies! i think i am just gonna have to test it out in a pool.... the mention of the housing possibly blocking the ir light though makes a great point! i may have to buy some extra ir lights and somehow makes them submersible and strap them to the housing to see.

any other thoughts/ideas?

thank you all i truly appreciate it!

I believe infrared light is absorbed readily by water, so it may not work underwater. Try shooting infrared with your camera through a bag of water to see how much IR is blocked.

Dan

Johnny,

A helpful question to answer is "Why do you want to shoot underwater using infrared?" What are you trying to accomplish? The answer to this may lead to interesting suggestions about how to accomplish your goals.

thank you all very much, i think we've found the answers weve been looking for. I appreciate everyone taking the time out to help answer my questions. It was very kind of you.

Best to you all and your underwater adventures!

-Johnny