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Old Oct 20, 2005, 11:36 PM   #11
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Using manual white balance is a good way to adjust camera settings in mixed llight sometimes, but only if done correctly. When you take the WB exposure, you should slightly underexpose a white card, otherwise the camera may not be able to discern the differences in R,G.and B values. A gray card should work well at any time. You can make your own with a photo editor and a printer. I select a fill color of gray at midrange value, and have my printer print it out using black ink only. Works perfectly when I need it. Which is not often, as I mostly shoot RAW, so WB can be modified as needed after the fact.

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Old Oct 21, 2005, 12:35 AM   #12
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use the palm of your hand
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Old Oct 21, 2005, 2:09 AM   #13
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I can recommend the WhiBal which has white, black, light and dark grey and is very portable.
http://www.rawworkflow.com/products/whibal/

PS there are pocket and studio sizes.:-)

Bill
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Old Oct 22, 2005, 6:56 PM   #14
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I use the Myers Digital Gray card.

Good value!

http://www.rmimaging.com/
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Old Oct 23, 2005, 9:24 AM   #15
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John H escribió:
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Anyone else wanna chime in on the subject in regards to white balances, and light meter calibration?

It seems there is a little confusion with White balance and ligth metering, and they are two totally different things..

Ligth metering is used when you want to properly set the aperture & shutter speed and take a well ILUMINATED picture (also called "balanced", and that is the begining of the confusion).

For this job, the best way is placing a gray card over the subject and let the camera or photometer read the ligth from it and suggest the best values. If you don't have a gray card, you can also read the ligth at the palm or your hand, but never use a white paper, or you could get an underexposed picture.



White balance is a nice feature included only in digital cameras.

With "old" analog cameras, when you shoot outdoors everything is ok; however, when you shoot indoors with tungsten ligth the pictures become orange, or with neon ligth the pictures become geen. To solve that, the old way is to place filtersat the top of your lens tocorrect the temperature of the ambient ligth, and then get true colors in your pictures.

With digital cameras, you don't need those filters anymore. Just set the white balance to any of the presets "cloudy, tungsten, halogen, etc", and the camera will "place" a digital filter to correct the colors. If you want to get more control, then use the "Manual White Balance". When white balancing,you shot to a WHITE paper and tell the camera "this color is white!!, not orange, not green, nor gray, just WHITE!!!" and the camera does the job. REMEMBER to change the white balance seting when you change of ambient ligth.
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Old Oct 24, 2005, 1:29 AM   #16
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msantos wrote:
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When white balancing,you shot to a WHITE paper and tell the camera "this color is white!!, not orange, not green, nor gray, just WHITE!!!" and the camera does the job. REMEMBER to change the white balance seting when you change of ambient ligth.
In many cameras, the exposure when taking the shot for white balance has to be set so the white paper is not overexposed, otherwise, there could very well be a color cast set in. For example: if the light has a yellow cast, but you overexpose the frame, the camera sees what should be yellow as white, and if you sore this information as manual WB, any picture you take with that setting will reflect that. If you use gray, or do not overexpose, the wetting will be carrect. The camera is simply looking for equal amounts of R,G, and B in the WB frame. This does not affect the exposure.

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Old Oct 24, 2005, 6:41 AM   #17
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msantos wrote:
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... When white balancing,you shot to a WHITE paper and tell the camera "this color is white!!, not orange, not green, nor gray, just WHITE!!!" ...
There is no color difference between gray and white.
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Old Oct 26, 2005, 9:57 PM   #18
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Let me amplfy on Bill's reply;

When setting (custom) white balance, the main thing is to have a have a reference image that reflects all colors of the spectrum evenly (eg., Gray; R=128, G=128, B=128 or White; R=256,G=256, B=256). The trick is to find a reference image that reflects colors equally. White copy paper does a poor job in that it has a strong blue bias. Kodak 18% gray card doesn't do a good job either since it was designed as an "exposure" reference and not a color reference card.

Cards that are specifically designed to be color neutral are WhiBal, Myers, and McBeth/Gretag.
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