Cinematography-Theory-And-Practice

ViewfinderMirror(closed section)Open sectionOpen sectionFilmMirror(closed section)AdjustablesectionLensSpinning mirrorFigure 10.33. (above) Adjustablerotating shutter. Shutter angleadjustment in video or High Defcameras is done electronically.Figure 10.34. (left) The spinningmirror shutter alternates betweensending the image to the viewfinderand letting the image reach the filmplane.ViewfinderMirrorImage pathReading Exposure with Ultravioletultraviolet light sources. They include Wildfire and Nocturn. When rescentpaints or dyes or with objects that naturally fluoresce, anincident reading is meaningless. The only valid means of assessingexposure is a reflected reading. A wide-angle reflectance meter willwork if you have one, or have an adapter for your incident meter. Ifthat is not available, a spot reading will work.EXPOSURE AND THE CAMERANearly all film cameras have rotating reflex shutters, which controlexposure by alternately rotating closed and open sections past thefilm plane. While the closed section is in front of the film gate, thefilm moves, while the open section is in front of the gate, the film isexposed (Figure 10.34). The exposure time of the camera is determinedby two factors: the speed at which the shutter is operatingand the size of the open section. The speed is determined by theexposure207