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-   -   greenish white preset (https://www.dvinfo.net/forum/jvc-gy-hd-series-camera-systems/106327-greenish-white-preset.html)

Ralph Mooijekind October 24th, 2007 04:34 AM

greenish white preset
 
last week i recorded some footage with my jvc-gy hd201e with hard disk recorder and had the white balance preset set on 5600k (daylight).

watching the footage on my computer i discovered that the images (especially the one with a lot of sky in the background) were a bit greenish (see link below).

http://www.xs4all.nl/~paper/jvc/green.jpg

this problem is easilly solved with the '3-way collor corrector' in FCP 5.1, so i'm not worried about that. my point of intrest is more about how the (left) image could become so greenish.

it might sound stupid but could it have something to do with the location an circumstances of shooting? it was at a shipyard in indonesia (close to singapore) where the sea water is rather green and while recording there was a thin layer of clouds at the sky.

so i wonder if the greenish images could be a result of reflection from the see to the clouds?
(i've heard a story that the dutch painters where famous for their panorama's with special light fall caused by the reflection from the sun in the rivers/sea). or am i talking nonsense and is there a problem with the white balance preset of my new hd201?

ralph

Shai Camerini October 24th, 2007 08:48 AM

did you used the preset white balance?

Ralph Mooijekind October 24th, 2007 09:00 AM

yes, i used the preset at 5600K (did NOT use the FAW)

Shai Camerini October 24th, 2007 02:14 PM

Never use the AWB!
Its like working with auto focus/auto iris it can change in the middle of the shot, and it uses the average of all colors instead of balancing the white only.
Do the WB yourself.
The preset is meant for known situations in emergency situations.

Ralph Mooijekind October 24th, 2007 03:36 PM

Quote:

Originally Posted by Shai Camerini (Post 764105)
Never use the AWB!
...
The preset is meant for known situations in emergency situations.

hi shai,

i did NOT use the Full Auto White balance (FAW) neither did the white balancing myself. i only took the risk of recording with the preset.

but can you explain the greenish layer? i would have suspected a red-ish (warm) of blue-ish (cold) picture if i had made a mistake with choosing the right white balance.

Todd Norris October 24th, 2007 04:38 PM

I have to agree with the other posters above. Rarely is exterior color temperature exactly 5600 degrees kelvin, so the preset is to be avoided if you can help it. It is best to manually white balance on a white card or something white.
As to why the image looks greenish instead of bluish...that is somewhat subjective. To me, your photo on the left IS a bit blue also. It's definitely cooler than the corrected image on the right. Another cause could be glare from the sun hitting your lens. That can sometimes cause a greenish cast in your images.

Petr Bastar October 24th, 2007 04:53 PM

My opinion is, that you can get better by using Paolos camera setting, to get better picture. If it was shot with default factory settings, you can really go better with Paolos. AWB will work better too.

Bob Hart October 24th, 2007 06:24 PM

You can expect green spill from dark green thick coastal vegetation over bright white sand. Use a white reflector as well and you get this green colour cast which when you correct it, causes the actors to look as if they have been rolling on a floor covered in diluted beetroot juice. This happened to me even after a manual white balance because I was still using two light sources of different colour only I didn't know it at the time.

David Scattergood October 25th, 2007 03:56 AM

I shot some footage on a building site some time ago now - the footage looked very much like your first pic on the left. Unfortunately, at the time, I didn't put much consideration into manually white balancing, but it's now one of the first things I do after turning the camera on.
It didn't help that it was one of those days which was really bright, yet lightly overcast and had recently rained: the puddles and 'sheen' cast some pretty bright reflections back. I was probably around 3/4000k out (one of the highest temp situations I gather)! Only just managed to salvage at least some of the footage via the 3 way colour corrector.

I get the occasional discrepancy when white balancing (I'd glossily laminated my white card to keep it in good condition...I'm not sure but this may sometimes affect the reading i.e. too much reflection bouncing back?)
Best to rely on your eyes - if the scene is 'warm' and the viewfinder still looks 'cold' then re do the balance.

David Scattergood October 25th, 2007 03:57 AM

Quote:

Originally Posted by Bob Hart (Post 764248)
You can expect green spill from dark green thick coastal vegetation over bright white sand. Use a white reflector as well and you get this green colour cast which when you correct it, causes the actors to look as if they have been rolling on a floor covered in diluted beetroot juice. This happened to me even after a manual white balance because I was still using two light sources of different colour only I didn't know it at the time.

Hi Bob - I'd be interested to know how you would you get round this problem now?
Cheers.

Shai Camerini October 25th, 2007 10:42 AM

Quote:

Originally Posted by Petr Bastar (Post 764195)
My opinion is, that you can get better by using Paolos camera setting, to get better picture. If it was shot with default factory settings, you can really go better with Paolos. AWB will work better too.

Paolos camera setting is meant for indoors shooting with artificial light only
there are another settings for outdoors.


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