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Old August 20th, 2008, 07:16 PM   #1
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Greenish images when preset is set to 5600K?

Hello all,

Out on day 3 of testing with the JVC, finding settings that we like, etc.

Today's testing was with 4 o'clock sun, not a cloud in the sky. We took several shots with several different scene files, using a scene average white balance, and then the 5600K preset. The scene average white balance (frame the shot then white balance as opposed to using a white card) also landed at 3700K. The shots look perfect, I wouldn't touch them with a single filter! When the exact same shot was taken with the 5600K preset, a greenish tone is very evident. We've found this REGARDLESS of the scene file (DSC, Superwide, TrueColor, HDCinema, etc...) Again, 3700K looks great, 5600K is definitely green!

How can this be? I've read in previous posts about the possibility of the white balance presets needing calibration?! Is this possible? Are there some menus buried in this camera? Any help would be appreciated!

jpb
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Old August 20th, 2008, 07:45 PM   #2
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Have you ever seen this before? It is possible there is a calibration issue.

Could you please post frame grabs of the scene at 3700K, 3200K preset and 5600K preset?

Also I wouldn't recommend the technique you described as "scene average white balance." Results can be unpredictable.
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Old August 20th, 2008, 08:27 PM   #3
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Agreed - the white card always rules (when the shoot matters). I will be happy to post some screengrabs first thing tomorrow morning.

jpb
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Old August 21st, 2008, 01:38 AM   #4
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3700k from late afternoon sunlight sounds interesting?

Can you show us a couple of grabs?

One thing that springs to mind is that you might be white balancing off of something that's not white. What are you using to balance from?
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Old August 21st, 2008, 07:28 AM   #5
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Files are attached. Thanks for the analysis!

jpb
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Old August 21st, 2008, 07:31 AM   #6
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Ok, NOW they are attached :)
Attached Thumbnails
Greenish images when preset is set to 5600K?-true_3700.jpg   Greenish images when preset is set to 5600K?-true_5600.jpg  

Greenish images when preset is set to 5600K?-sw_3700.jpg   Greenish images when preset is set to 5600K?-sw_5600.jpg  

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Old August 21st, 2008, 08:05 AM   #7
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Outdoor settings with lots of grass and open shade coming through trees will have quite a bit of green in them. Your samples however seem to be pretty open scenes which shouldn't be this susceptible to the reflected foliage effect.

Which JVC camera is it? I've found that the 200 which I have reports completely different white balance kelvin numbers than a 100. Both wb accurately to the same picture, but the 200 gives a much lower number. I'm pretty sure the 100 is actually closer to the mark here too, but I haven't had them together with time for real analysis. I just look at the numbers reported from my camera as comparative references when trying slightly different looks in a mixed light scene.

The "scene average" wb is really dangerous though... I can't imagine EVER using this. Adjusting the green overall for your outdoor scenes in post is no big deal, but trying to match different scenes with the likely skewed color could be a real nightmare.
Remember the white card outdoors doesn't have to be right in the shot - it can be anywhere getting the same type of sunlight as the subject, like next to your camera.
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Old August 21st, 2008, 03:14 PM   #8
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The camera is the HD200. Float on the thumbnails, the naming will make sense.
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Old August 21st, 2008, 03:28 PM   #9
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The number and white lines on the third image leads me to believe these are screen captures from within FCP as opposed to exported stills from the actual video stream. What happens if you export actual stills? Just trying to verify that this isn't a monitor calibration issue/Colour Space Profile issue.
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Old August 21st, 2008, 04:56 PM   #10
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It is from FCP, but that being said, the issue is only present with these shots. Take my word that this is not a monitor calibration issue as I get it on the camera's LCD, a CRT monitor, etc.

To reiterate, the non-green images are where I did take an average white balance. I'm having issues when I select the 5600K preset - that's the weird part.

jpb
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Old August 22nd, 2008, 02:00 AM   #11
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It could be said that the top image on the LHS has a red tint! There is always a danger in making side by side comparisons like this. If you took your preset 5600k image away and looked at it on its own many people would say it looked OK. When you look at the 2 side by side a difference becomes apparent and your mind becomes more focused on the difference.

However..I'm inclined to agree with you, it does have an overall green inbalance. The image on the left has a red inbalance.

I'm interested in why both the preset 5600k images are different as are the two balanced images?

What source of white did you use to white balance. This is important. This is one of the most common sources of colour tints from white balancing. We use warm cards to 'cheat' our cameras on some shoots. We have a book of white cards with different shades of white.

If you are suggesting that the 5600k preset is what is at fault here then it's worth remembering that 5600k might probably not have been an appropriate temperature reading for those conditions. I'm not familiar with US weather but in Europe late afternoon and very early morning sunshine will give you higher readings.
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Old August 22nd, 2008, 09:42 AM   #12
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Quote:
Originally Posted by Stuart Campbell View Post
It could be said that the top image on the LHS has a red tint! ....
Hmmm. The top left preset looks good on my monitor. The brick is the right color. The skin tone is a little warm. The grass has that "give me some water" look. The leaves on the tree look realistic. The sky is right on. The football is correctly hued. I'm not seeing a problem. Looks slightly warm...but not green.
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Old August 23rd, 2008, 07:36 AM   #13
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Using the preset WB is no guarantee of pleasing end color look. Daylight can be much cooler or much warmer. The presence of foliage can add a green tint. It's a safe more for run and gun situations, and when you want to see the effects of the changing natural light.
You don't white balance to shoot the sunset for instance, because it takes out the warm colors we associate with it. Then, you get your color "look" in post, and if multiple shots outdoors are done with the preset, this will probably go quite quickly.

White balance with a white card will give you an accurate color for the light the white card is in. However, many people gravitate to a warmer than neutral look, and side-by-side, the neutral image looks colder and blueish. Again, I'd prefer to tweak this in post, especially for a "dramatic" project. The danger is also that if you move from shade to open sun with your set wb to one of these, you can have more exaggerated off color than a neutral setting. The HD200 gives kelvin readings I don't trust as absolute - but are still useful as RELATIVE readings.

But to see if you have a calibration problem (camera or otherwise), we'd have to see a more scientific test. Frame grabs from the same scene with white cards & preferably color chart too, with preset and properly deployed white card manual settings. The cameras settings should be stock, or one of the scene settings published here that we are familiar with.

Simple answer is that if you use the wb preset, be prepared to adjust for your color look afterwards.
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