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Canon XL and GL Series DV Camcorders
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Old October 13th, 2005, 02:28 AM   #1
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white balance

I'm sorry for this question guys, but i'm so new to Dv.. can someone explain to me white balance..is it to set the same color tone for the same scene incase you shoot it in different days and the lights move...is it to keep continuity to the film? please someone explain it to me...thanks
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Old October 13th, 2005, 06:25 AM   #2
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White balance is used to 'fix' the color on recorded video/still pictures

the problem is that all light sources use different color light. Lights are not simply emitting white light but rather have some specific color (some are even worse by changing colors in a spectrum)

What white balance is is that you can tell the camera what kind of light source (what color) you are using and so the camera can correct the colors.

Most cameras have presets such as sunny, overcast/shade, tunsgten, ... and then a custom white balance.

The custom white balance allows you to have the camera test the light and find out the white balance bias on its own. You do this by filming a white or neutral grey card and then the camera can check the bias because the 3 color components red green and blue should be the same on white or neutral grey.

Try it out. set your camera to a specific white balance that is wrong and look at the video then change the setting.

There is also autoi white balance which is ok if you have lots of changing conditions and do not have the time to change but the problem is that it will constantly change the white balance so you often end up with skin colors changing over time and such.

it is always better to use a specific white balance either a preset or custom.
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Old October 13th, 2005, 06:49 AM   #3
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What about twisting Michael's idea the other way around: When we make visual perceptions of the world around us, our brain tends to interpret objects which are close to white as pure white or neutral gray ones. For example, think of the sun set of a gray autumn day. When you sit indoors and have the lights on and look through a window everything outdoors appear blue for a moment. Now, if you really get outdoors, you'll suddenly find out that it was not blueish but instead all so gray. The reason is, the lights indoor have mislead your brain to interpret the outdoor conditions according to the indoor color temperature. When you walk outdoors, your brain changes the interpretation.

Evidently, no technical machine had similar kind of wisdom to interpret colors. That's why cameras have the white balance enabling the user to tell the camera which object should appear white. In other words, you are assumed to put a white object in front of the camera, and then, the different color channels are balanced such that the stored data of the object becomes white or neutral gray.

Automatic white balance tries to guess the color temperature, but it can also get it completely wrong. For example, that's why there are so many images around of greenish background sky behind the aurora borealis. In reality the aurora borealis is green (or red) but typically the background sky is blue (unless the whole sky is about northern lights). The automatic white balance does not manage to adjust the white balance, and thus, also the background sky appears greenish.
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Old October 13th, 2005, 10:39 AM   #4
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Hi guys. I'd like to jump in here with a follow up question. When you use a grey card or white card for while balancing, will any grey or white source work or should one buy an "official" one? Also, should this be done with or without zoom? Thanks in advance.
Sprague
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Old October 13th, 2005, 10:46 AM   #5
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It has to be a neutral color. Neutral means where all components R G and B are the same value
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Old October 14th, 2005, 02:06 AM   #6
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Quote:
Originally Posted by Michael Salzlechner
It has to be a neutral color. Neutral means where all components R G and B are the same value
Yes, neutral colour is the way to get an accurate white balance. You can also get some very nice effects by white balancing to a coloured card (I sometimes use a card with a slight blue or green tinge).

Richard
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Old October 14th, 2005, 03:15 AM   #7
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Quote:
Originally Posted by Allen Thok
I'm sorry for this question guys, but i'm so new to Dv.. can someone explain to me white balance..is it to set the same color tone for the same scene incase you shoot it in different days and the lights move...is it to keep continuity to the film? please someone explain it to me...thanks

Dear Allen,

Not sure where this post will appear but the former replies seem to be in the category of "much more info than requested".

White balancing tells the camera what light temp. you are shooting under.
Each lighting situation is different and requires a manual white balance or auto set up or specific cam setting for each scene. Interior lights are usually 3200K, full sun is usually 5600K and outdoor shade is usually 7600K. Manual white balance is used to set your camera up for recording in the actual lighting situation you will be taping in.

Also understand the Neutral Density filter settings (to cut down on the amount of light reaching the lens), and employ it if needed..

Learning the physics of certain color temps may be scary. But just use AUTO WHITE BALANCE and you should be fine for now.

Please post back with any further questions.

Good Luck

Stephanie
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Old October 14th, 2005, 09:21 AM   #8
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Quote:
Originally Posted by Stephanie Wilson
Not sure where this post will appear but the former replies seem to be in the category of "much more info than requested".
Interesting, how different people understand what is primal in different ways. Stephanie -this is really hair splitting and everything is in the eye of the beholder- but in my eyes your reply leaves unanswered the primal and crucial question, what is the color temperatur. "Color temperature" is nothing but a name or label, and without knowing what it is, sentence "White balancing tells the camera what light temp. you are shooting under" has little meaning.

The nice thing of this kind of forum is that there are so many different kind of people around. If somebody's answer does not please one, there will always be another explanations posted as well. As a group, the large number of people tend to get the explanations eventually to converge towards good answers.
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