ABSTRACT
As we discussed in charge-coupled devices (page 20), the CCDs in the camera respond to light and convert the variations of brightness into variations in the electrical signal output. There is a minimum light level required to produce any signal. Below this level the camera processing circuits produce a uniform black. This is called black clip (see figure opposite). As the intensity of light increases, the signal increases proportionally until a point is reached when the signal is limited and no further increase is possible even if the light intensity continues to increase. This point is called the white clip level and identifies the maximum allowable video level. Any range of highlight tones above this level will be reproduced as the peak white tone where the signal is set to be clipped. Variation in the brightness of objects will only be transferred into a video signal if they are exposed to fall between the black clip level and white clip level.
