... situations. To mask some of the noise at low light levels, consumer cameras often use a setup, or black level, of zero IRE, rather than the 7.5 IRE broadcast standard. Some cameras that automatically ... the darkest and brightest parts of the picture on a reflectance light meter. In practice, actual contrast ranges are rarely measured using a meter. A subjective analysis based on camera output ... suspicious, so a number of years ago I set up an ordinary candle one foot away from a white square on a black background. I tested two cameras. The first was a popular CCD camera requiring four LUX...