Cinematography-Theory-And-Practice

Figure 9.35. (top) Shot on thecamera, this curve shows thegamma at normal, which is .45 onthis camera.Figure 9.36. (bottom) With thecamera set at a high gamma, the picturebecomes very contrasty, whichwe can see represented as a muchsteeper curve.THE CURVEThe video signal is largely the same as film’s response to light and thecurve as seen on a waveform monitor is the same as the Hurter andDriffield or D log E curve that is discussed in the chapter Exposure.Different terminology is used for video: in film densitometry, thehighlights are called the shoulder, and the dark areas are called the toe.In video the brightest areas are called the knee, and the darkest areasof the frame are simply called the shadow areas. In the illustrationsin this chapter, a gray gradient from black on the left to pure whiteon the right was shot with an HD camera and the waveform monitorwas photographed. This gives a more readable representation ofhow the various controls of knee, gamma and black gamma changethe image. These controls apply to all types of video except RAW,which records the image without any alterations; however, it is criti-HD cinematography177