Adam Maas <[EMAIL PROTECTED]> wrote: >There is a photographic myth with 18% grey. The myth is the idea that >your camera's meter assumes 18% grey, which is incorrect. Meters assume >roughly 12.5% grey (there is an ISO standard).
Actually, one of the amazing things is that there *isn't* an ISO standard at all for light meters. The only one is an ANSI standard (ANSI PH3.49-1971 if you're truly obsessed by this kind of thing). And it does specify somewhere around 12.5%. >Grey cards are 18% for the reason graywolf explains, as well as due to >intense lobbying of Kodak by Ansel Adams (Who wanted 18% grey because it >is 50% luminance and right in Zone V). But overall, most scenes do indeed >average out to 18% grey. Which is why Kodak grey cards come with instructions to meter off the card (18% grey) and then open up 1/2 stop - to compensate for your camera's meter, which should be calibrated somewhere around 12.5%. I say "should be" because manufacturers are notoriously variable. In one of Galen Rowell's last columns he wrote about testing two of his new Nikon F100's and finding them almost a full stop different in metering the same scene. He stated that he routinely did this testing because he never got two cameras that were alike and he wanted to know what to expect from each camera he was going to be using. And these were not budget cameras he was using. -- Mark Roberts Photography and writing www.robertstech.com
