Tuesday, April 26, 2011
Master The Family Of Angles
This fundamental aspect of lighting will help you figure out how to light anything, anywhere, anytime
Most professionals are well versed in lighting techniques for their particular subject matter. Food photographers know how to light food. Jewelry photographers know how to light jewelry; wedding photographers know how to light brides. We’re presenting the following excerpt from Light: Science & Magic by Hunter, Biver and Fuqua (Focal Press) because the ideas in this chapter will help someone who’s knowledge-able in lighting one kind of subject to efficiently light another. In the ever more competitive field of professional photography, jewelry photographers need to be able to light food. Wedding photographers need to be able to light jewelry. And everyone needs to be a “run-and-gun, get it done and move to the next shot” kind of photographer. Understanding the management of reflection and the family of angles will make you a better and more efficient photographer.
—Christopher Robinson, Editor
Photographic lighting is primarily an exercise in reflection management. Understanding and managing reflection, for the result the photographer wants, is good lighting. We will look at how subjects reflect light and how to capitalize on those reflections.
Light can reflect from a subject as diffuse reflection, direct reflection or glare. Most surfaces cause some of each of these three types. The proportions of each type of reflection vary with the subject, and it is the proportion of each reflection in the mix that makes one surface look different from another. For now, we do not care what type of light source might be producing any of the following examples. Only the reflecting surface matters. Any sort of light, strobe, tungsten or fluorescent could work.
Diffuse reflections are the same brightness regardless of the angle from which we view them. This is because the light from the sources is reflected equally in all directions by the surface it strikes. Figure 1 shows a diffuse reflection. In it we see light falling on a small white card. Three people are pointing their cameras at it.
If each of these individuals were to photograph the white card, each of their pictures would record the subject as the same brightness. On film, the image of the card would have the same density in each negative. Neither the angle of illumination of the light source nor the camera’s angle of view would affect the brightness of the subject in such a picture.
Other than in lighting textbooks, no surfaces reflect light in a perfectly diffuse manner. However, white paper approximates such a surface. Now look at Figure 2. Notice that the scene contains a mostly white piece of sheet music.
There is a reason that we chose to put the white newsprint in this particular example. All white things produce a great deal of diffuse reflection. We know this because they appear white regardless of the angle from which we view them. (Walk around the room you are in now. Look at the white objects and the black objects from different angles. Notice that the apparent brightness of the black objects may change with viewpoint, but the white objects stay about the same.)
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