[meteorite-list] Re: THE ART OF PHOTOGRAPHING Pictures 101
From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Sat May 21 16:05:28 2005 Message-ID: <428F9462.5737270B_at_bhil.com> Hi, Before the first days of auto-exposure calculation in cameras (film then), the problem has always been to sum all the lights and darks in a potentially infinite range of images to determine a single correct exposure. The original solution that underlies auto-exposure and all the sophistication of today's cameras is to assume that if all areas of the proposed image were mixed together like paint, the overall outcome would be an 18% gray. For decades, Kodak sold 18% gray cards and sheets for photographers to calibrate their exposures manually, even before "auto" exposure. Even though they may be using a $10,000 digital camera, most (probably all) professional photographers have yards and yards of 18% neutral gray backdrop material. 18% gray is the starting point for "correcting" exposure if needed. It will produce the best results, just like Anne said, for the reason that the underlying algorithms of the camera's electronics are build on that supposition. Sterling K. Webb ------------------------------------------------- Impactika_at_aol.com wrote: > And I never use a black background, it just drowns out the specimens. I > found some file folders in a very soft, neutral shade of gray and I find that it > does not distort the color of whatever pieces you put on it, being a green > Tatahouine, a very dark Kainsaz or a yellow Libyan glass. Received on Sat 21 May 2005 04:04:50 PM PDT |
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