What settings to use when shooting underwater?

[Highlander]

Hi,
I am using Sony HVR-A1 and I have had some problems with the quality of the video. If I am close to object everything is fine, but if I shoot wide areas or “landscapes” video becomes grainy and noisy, even with good lighting conditions. I have tried to shoot with different settings, (both auto and manual) but I still can’t get it right. I know that my camera isn’t very good at low light but still.

After watching Jonathans http://www.blueworldtv.com/season_2.html I know that it is possible to shoot good quality underwater video with my camera. Jonathan, if you are still using this same model how do you manage to get so good shots?

Can you guys please give me some advises on what settings you are using when shooting underwater even if you are not shooting with this same camera.

-Miikka

[Jonathan Bird]

Miika,
Any way you can post some video someplace so I can get a look at what you mean? Hard to diagnose the problem from a description. The A1 is not great in low light, but that depends on your definition of low light. I have never had an issue during the daytime, no matter how deep the water. Only at night or in caves, and even then, it only takes a splash of light to work.

One thing about the A1 is that in low light, they seem to combine the pixels so the picture gets less sharp, but not as grainy as other cameras. My Canon XH-A1 gets really grainy as the gain goes up in very low light, which makes compression later for blu-ray look weird because the codec can't handle the detail in the grain. The Sony doesn't have this problem because they force the camera to lose detail in low light.

That being said, I am primarily shooting with an FX7 underwater now, which is a tad cleaner. Still, I think the Sony A1 is one of the better early HDV cameras for underwater. It actually delivers more detail (horizontal resolution) than a Z1 in good light due to its 3MP imager, and is a good bit smaller. But the Z1 kicks its butt in low light.

Tell me about your housing and optics. Are you using a red filter at depth? They take out all the light! If your camera is running more than 3 dB of gain at any point, it's going to be noisy. Don't use a red filter if the light isn't good. Remember that at say 60 feet, a red filter takes out something like 4 stops of light!! (Because there just isn't much red down there). If you try to use a red filter at that depth, no matter what camera you use, unless the sun is blazing and you are in very clear tropical water, the camera will be running at 6-18 dB of gain. No camera looks good with that level of light.

When I use my red filter, I always check the exposure on the camera and if the red filter is going to cause me to need more than 3 dB of gain, I turn it off and use lighting instead.

Jonathan

[Highlander]

Miika,

Tell me about your housing and optics. Are you using a red filter at depth? They take out all the light! If your camera is running more than 3 dB of gain at any point, it's going to be noisy. Don't use a red filter if the light isn't good. Remember that at say 60 feet, a red filter takes out something like 4 stops of light!! (Because there just isn't much red down there). If you try to use a red filter at that depth, no matter what camera you use, unless the sun is blazing and you are in very clear tropical water, the camera will be running at 6-18 dB of gain. No camera looks good with that level of light.

Jonathan
Jonathan,

I'm using Ikelite’s housing with Raynox HD 5050pro lens and dome port to match. I use a red filter to a depth about 50-60 feet. I think most of my problems come when I use red filter too deep and when the exposure is not "right". Have you ever noticed any softness on the left side of the picture when using this raynox lens. I thought that it was supposed to be sharp in every corner? I'll try to get those samples to you...
-Miikka

[Jonathan Bird]

Miikka,
The Raynox is pretty sharp. Focus at about 3 feet and you are good to infinity. The red filter will definitely make the image grainy if the light is not sufficient to begin with. Remember, there is very little red light at 60 feet. Unless you have a bright overhead sun, you will end up with a lot of gain on the video using the filter, and that makes it grainy. You lose SO much light through the red filter at that depth that you really need a lot of light to start with.

Jonathan

[Carl]

All,

I am editing through about 12 hours of tapes from the recent Galapagos trip (see Pacific thread, it is worth it ! ).

As to video settings I have the following comments/suggestions:

1. ESPECIALLY when diving with Jonathan, and even when not, LISTEN to Jonathan: he is usually right.

2. Learn to really be still. Let the scene continue to develop in front of you without moving. Only move when you really need to follow the action. Transitions from still to moving really need to be concentrated on !

3. He preaches it and now I get it: NEVER, NEVER, NEVER use automatic focus. I had much less trouble with "seeking" behavior with the VX2000 setup than the new FX7 HD setup. Jonathan can explain it, but the HD sensors are less adept at knowing what YOUR brain wants them to focus on than the higher end standard definition cams were.

4. White balance and red filter combinations: In Galapagos it is nearly impossible to run lights. Distance to subject are different than reef work and the vis, at its best is not great with tons of particulates. Hence you run white balance for conditions and get rid of the red filter when light gets too low. Jonathan's suggestion of watching gain and getting rid of the red filter when gain hits about +6 is productive of less soft/grainy images. When you are shooting through milk (non-fat or 2%? if it is whole milk, it's not worth shooting) some amount of softness looks mandatory.

5. REPEAT number 1: Listen to Jonathan, he is usually right !

Comments obviously welcome!

[Jonathan Bird]

Thanks Carl! It's about time someone said it! :D

Many years of screwing up have taught me many lessons.

Now if I could get Pierre to listen to me on the red filter, we would be getting someplace. ;)

Jonathan

P.S. HD cameras are very sensitive to focus because you can SEE it when they are only a tiny bit out of focus. SD was a lot more forgiving. I never found that autofocus was worth a damn in either.