> Under the RGB scheme you describe, the contrast and brightness information comes from the RGB sensors. The only way it knows this is because 0, 0, 0 is less bright than 255, 255, 255, and the two of them give a lot of contrast. So contrast and brightness are based on the color values. Nope. The 1005-pixel CCD isn't the only part of the F5's matrix metering system. It also has the traditional metering components. Thus, the traditional meter is providing both overall (EV, or brightness) information, as well as some contrast info (differences between the matrices). The color information is then added to this to make an exposure determination. In a traditional meter, a high EV value detected by the meter means "to get to 18% gray I need to stop down the lens." In the F5, a high EV value detected by the meter means "wait a second, that's yellow, which doesn't reflect the same as gray, so instead of stopping down to the value I would for 18% gray, I'll stop down a bit less." >If, according to a normal meter, a grey card in the sun gives EV 16 and a white card in the shade gives EV 16, how is the white card in the shade brighter?? Yes, in theory, the F5 meter could detect gray versus white in the scenario you describe. Whether it actually does is subject to guess, as Nikon has not chosen to tell photographers how the CCD information is integrated with the rest of the metering system. Thom Hogan Executive Editor, BACKPACKER Magazine author, The Nikon Field Guide (Silver Pixel Press) www.bythom.com
