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Old 06-15-2005, 08:35 AM   #4
Mike McCarty Mike McCarty is offline
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Joined: Dec 2001
Location: Tulsa, Oklahoma
Posts: 2,674
Kim,

I'm new to the gray card but I like it. Mine is a 8" x 10" piece of cardboard with a neutral (rather dark) gray covering one side. The neutral gray is designed to reflect 18% of the light hitting it.

I'll read you what it says from the instructions on the back of the card:

"Light meters and camera meters are calibrated to average the light reflected off a scene so that the <film> will record the scene as average. The average scene will reflect approximately the same as a gray card or 18%. However, if the scene is not average, it is necessary to make an adjustment to the setting of your meter. This is the time to use your gray card. It will help you determine the proper exposure adjustments."

I've been using my gray card a lot lately outside taking progress photos of a painting. I'm getting the best color renditions I've ever gotten using this method. I think that if you can, it's probably the best white balance exposure method there is.

Again from the instructions:

"First, it is important that the gray card and your subject are receiving the same illumination. Second, position the gray card so there are no shadows, glare, or hotspots on the card itself. By holding the camera approximately 6" from the card, you will get the appropriate reading of light reflecting off the card. When making your reading avoid casting a shadow on the card. "

Cameras will do this differently so from here you need to consult with your own manual, but mine goes something like this: In the "P"rogram mode, I set the wb to preset, push and hold a wb button on the back of the camera until a preset light begins to flash. I then position about 6" away, fill the view finder with the card and snap the shutter release. I then get a flashing "good" indication that the procedure worked. It will use that setting until I change it.

It's easy to accept things as "OK" when you don't have anything to compare to. I think I get pretty good service out of the Auto WB setting outside, but I wonder. I may make some outdoor comparisons.

I've not figured out how to use the card for taking sunset pictures. When the light source is your subject where do you place the card?
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