Reply to Thread

Message:: [QUOTE="jb_depew, post: 2803932, member: 88227"]The kind of camera you're using aside, much of a camera's ability to capture an accurate exposure of a coin has to do with the camera's meter. A camera's meter is a device which "measures" the amount of light in front of it based on the tonal value of what makes up the bulk of the picture. Imagine the world (everything you can see) as you would in a black and white movie... like Schindler's list or wizard of Oz. Everything on a scale of white to black, on a scale of 1% black (very light) to 100% black (pitch black). A camera is always metering it's exposure to 18%. 18% is the color of green grass (as it would look in grayscale). What this means is that if you photo a coin (or anything for that matter) against a predominantly white background, it will generally be underexposed (dark). The camera sees lots of white, and is bringing the entire exposure to a baseline of 18%. If this makes no sense, photo a coin against white, and then try a green backdrop. Fancier cameras will allow for spot metering, which will take the meter value just from the very center of the frame (the coin), and thus return more accurate results, but I suspect most cell phone cameras use matrix metering, which measures the entire scene, background included, to determine how light or dark an exposure should be.[/QUOTE]