Lighting Tips and those nasty background GREENS

[pakman]

I'm still relatively new to video but one of annoying things I come across in my footage is where the background/ water that it outside of the light coverage gets that nasty green (see attached screen grab - pre editing; I know I know, overexposed the red frogfish; Sony HC7 and twin 24W HID's). The foreground that is within my light coverage will show proper color but trying to adjust the color in post just throws everything off if I'm trying to color adjust the background green.

What can I do to avoid those nasty greens...? I guess if the froggies were facing a bit differently, I could have used the coral to fill up my screen?

Any other tricks, tips you would recommend?

 

[DaFireMedic]

I'm still relatively new to video but one of annoying things I come across in my footage is where the background/ water that it outside of the light coverage gets that nasty green (see attached screen grab - pre editing; I know I know, overexposed the red frogfish; Sony HC7 and twin 24W HID's). The foreground that is within my light coverage will show proper color but trying to adjust the color in post just throws everything off if I'm trying to color adjust the background green.

What can I do to avoid those nasty greens...? I guess if the froggies were facing a bit differently, I could have used the coral to fill up my screen?

Any other tricks, tips you would recommend?

I think Dr. Bill was having the same concerns with the HC7, and posted a thread about it somewhere. I'm not sure if anyone had definitive answers though.

Do you have After Effects? If so, you could mask the green area and adjust the color within the mask. Blur the edge of the mask to help it blend. It would be somewhat tedious, as you would have to adjust the mask shape every few frames as the video moved, but I have done it over several minutes of video before with good results (adding blue sky, etc. to topside video stuff). I know that it would be better to take care of it before post if possible, but it goes faster than it sounds.

 

[Annie Crawley]

The trick with getting a blue background and using your lights is to white balance with the red filter on and the lights. If you do this then you get a blue background. I don't know if with your housing you can white balance with the HC7, but that is the trick to getting blue backgrounds with your lights. That can be done only if you can white balance, but you want to run some tests.

 

[pakman]

thanks Annie, will try that next time. Can't remember if I had the red filter down for the above shot. The HC7 is a bit touchy on getting a good MWB lock, especially if there isn't a lot of light.

 

[Annie Crawley]

That happens with ALL cameras not just yours. You must have good light to white balance. Sometimes if I am on a deep dive without lights, I will white balance when still in shallower water just in case I can't at depth. I also try and bring my lights on the deep dives for this reason. Makes a HUGE difference. I always use my lights with red filter down and white balance off the light area when I want a blue water back ground.

Any other questions? I will be diving for the next three days so if you do have any, I will not be back on line until Thursday or Friday....

 

[DiscoverTheBlue]

I personally prefer using a filter with a magenta or pinkish tone for filming green water. I find that using the red / orange filter in green water casts an awful yellow-mucky tint to the footage. (Of course - this is not the case in blue water, which is what the orange filter is actually intended for at approx 7 - 20 m depth). Check out this green water filter as example:
Equinox | 37mm Underwater Color Filter for Greenwater | 37MMGW |

Or this (cheaper) - though it's actually designed for photography:
M A G I C - F I L T E R S

Another thing you might want to try is setting your WB to "indoor". This will give everything a blueish tint. Now, however, it depends what kind of lamps you're using: if they're "daylight temperature" (somewhere around 4500 to 5500 K) you might find the background pleasing, but the actual object you've lit up has a blueish tint. If they are halogen or similar (around 3000 K) you should have very nice colors on your lit up subject and find that the green water in the BG has now a blueish tint.

Hope this helps!

 

[drbill]

Yes, this is a problem I've encountered with the HC-7 as well, Pakman. I was hoping mine was just a lemon but it appears as if the problem may be more common. The thing that really irks me is that I've NEVER had this problem with any of the five other Sony camcorders I've used in my housing. Areas outside the illuminated part of the frame were exactly what they should have been... dark shadows, no hint of green.

I'm not sure I understand Annie Crawley's suggestion to turn the shadows blue. Shadows have always been dark in my experience, only background water should turn blue. Right? Hmmm... just took another look at Pakman's still and that IS water in the background so now I understand. What I don't understand is why bottom substrate outside my area of illumination should be green rather than shades of gray.

 

[DaFireMedic]

Just an After Effects test, I would have to dial it in more and streamline it for video editing:

If one of Annie's or DiscoverTheBlue's suggestions works for you, it would be far better to take care of it before post. Just cruising around the reef, I could correct footage at what I feel is an acceptable rate but I'm not sure how fast this technique would work if you had a few fish out in the water column with no reef in the picture. It could get real slow.

 

[mdmbike to scuba]

Nice work DaFireMedic. Now is it me or is there some red dots in the background. Mark

 

[DaFireMedic]

Nice work DaFireMedic. Now is it me or is there some red dots in the background. Mark

It's just you.....

Lol...actually, I don't really see any, just what was in the unedited photo, but my color vision is below average.