Cinematography-Theory-And-Practice

III, which we do by counting “up” two stops to get f/8. Commonsense tells us that if we photograph the same scene at f/8 instead off/2, it is going to come out much darker: the background will not beNothing has changed in the actual set; we have changed the valueof the final print by “placing” the value of the background differently.But what’s the flaw in this ointment? There is more in thescene than just a gray background, and whatever else is there is goingto be photographing lighter or darker at the same time. This bringsus to the second half of the process: “fall.”If you place a certain value in a scene on a certain zone, othervalues in that scene are going to fall on the grayscale according tohow much different they are in illumination and reflectance. For ourexample, let’s assume we are using a Pentax Spotmeter that has a-to set the lensaperture, adding adjustments for filter factors, and so on.A Zones ExampleLet’s try an example. We are lighting a set with a window. We set a10K to simulate sunlight streaming in through the window. We thenread the curtains and the spot meter indicates f/11. We have decidedthat we want the curtains to be very “hot” but not burned out. Onthe film stock we are using today, we know that white “burns out”of the camera: it will be f/4, right?We then take an incident reading in the room where the people willbe standing. The incident reading is f/2.8. This means that peoplestanding in that position will photograph one zone too dark. Maybefor this scene that’s OK, but let’s assume we want to actors to havenormal exposure that will result in normal skin tone values. In other To correct the situation we have to change the balance. If we justopen up the lens, we are shifting the placement of the curtains andthey will burn out. We must change the ratio of the illumination,not just shift the aperture of the camera. We can either tone downthe 10K hitting the window with a double scrim (one stop) or wecan raise the exposure of the subject area by increasing the light levelthere one stop. Either way are manipulating the subject values of theforeground to “fall” where we want them, based on our “placement” values where we want them and then see where the curtains “fall.”It’s the same thing. By reading the scene in different ways, you can“place” the values of the negative where you want them to fall.Placement is important in determining subject brightness rangesand contrast ratios and in reading subjects that you can’t get to foran incident reading. In order to expose by placement, you mustpre-visualize which zone you want a subject value to reproduce as.For Ansel Adams, pre-visualization was what it was all about, andremember, he dealt mostly with landscapes where he had no controlover lighting. Since we usually control the lighting, we can take previsualizationone step further.cinematography206