Cinematography-Theory-And-Practice

TYPELAMP COLOR SHIFTCCTDIRECTIONDEGREE OFSHIFTIncandescent / TungstenHalogen Orange-red Lower MarkedFluorescent Not discernible Negligible NegligibleMetal Halide Blue Higher DrasticMercury Not discernible Negligible NegligibleTable 16.4. Most light sources shiftin color when dimmed.WORKING WITH STROBESThere are several types of strobe lighting for cinematography. Themost widely known is Unilux; Clairmont Camera also makes strobeunits. Strobes are generally used to create a different look for a shot.The fact that the strobe fires for a very short time means they havethe ability to freeze motion. Several units can be controlled togetherfor a greater number of heads. Frame rates of up to 500 fps are possible.The strobes are fired by a pulse from the camera that signalswhen the shutter is open. Any camera that provides such a pulse iscompatible with the system. In some cases a pulse contact is addedto a moving part of the camera, and this provides the sync signal tocontrol the strobe.Strobe lighting in film has three basic uses: tungsten heads), which can be a tremendous advantage whenshooting ice cream, for example. flash can be as short as 1/100,000th of a second, and as a result,the image is “frozen” and appears sharper than if photographedon moving film at standard exposures. with a small power input.It is often used in spray shots of soft drink cans being opened: thestrobe effect captures each droplet of spray crisply. In fact, it canbe too sharp for some people. In shower scenes for shampoo commercialsit can appear that the shower is a series of razor-sharp dropsrather than a soft spray. As a result, for beauty applications, it iscommon practice to combine Unilux with tungsten lighting. Inmost cases, the Unilux light is balanced with an equal amount oftungsten within a range of plus or minus one stop. This presents aninteresting exposure problem.All strobes are daylight balance, and you will need to use gels orfilters if you are combining them with incandescent lights, which areoften used to avoid flicker. When mixing with tungsten, use CTOon the strobes to match color temperature.Strobe ExposureConsider this situation: you are shooting at 96 frames per secondand the desired effect is equal amounts of tungsten and strobe lights.Every time you increase the frame rate of motion picture camera,you are decreasing the amount of time the shutter stays open: youare decreasing exposure. 96 fps is four times faster than normal, andthe shutter speed is 1/200th of a second instead of the normal 1/50th(assuming a 180 shutter). This is an exposure loss of two stops.This is simple enough to deal with; to achieve a f/5.6, for example,you light to an f/11. But the same is not true of the strobe lighting.The strobe is instantaneous: it fires for only a few thousandths of asecond at some time while the shutter is open, and as a result, it istechnical issues317