Using the Camera CHAPTER 7 when a picture is overexposed, all of its tones will appear unusually light. even fairly light tones in the scene will block off, whereas darker areas of the scene will often be easier to discern than normal. stopping down a little improves reproduction in light tones but reduces the visibility of shadows. However, it is impossible to electronically compensate for grossly over- or underexposed areas. they will have little detail. Again, lowering the video gain setting is not a good solution. it will simply reduce the overall brightness of the image (figure 7.18). 157 7.16 AUTOMATIC EXPOSURE if judging exposure is a matter of artistic choice, how is it that so many video cameras utilize an automatic iris most of the time? leaving aside those peo- ple who would otherwise be careless about exposure, the auto-iris is a useful tool when you are in a difficult spot. it continually adjusts the lens aperture to maintain an average video signal. Under typical location conditions, whether outside or inside, light levels can change considerably as the camera's viewpoint changes. if you were to walk around a location with a light meter, you would probably see its needle bouncing up and down each time you repositioned. the camera may need to