Moving Images, Understanding Media

Chapter 4 Storytelling with Light 127

to move from a wide to a telephoto shot. In other words, you can “zoom

in” or “zoom out.”

A tool of cinematographers that complements lenses is the fi lter. Glass

fi lters can be placed in front of the lens to alter the light that reaches the

camera. Filters can cut light without aff ecting colors, reduce light in certain

areas of the frame, polarize light to help with skies, change the colors of a

scene, or induce many other visual eff ects.

As seen previously, the core task of the cinematographer is to control the

quality of the light that is being recorded. Th ere are three basic parameters

that shape the essential properties of the moving image: focus, exposure, and

sensitivity.

Factor One: Focus

First, focus is the point at which light rays converge so an image or view appears

sharp with a normally functioning eye or lens. A lens must be adjusted—either

manually or automatically—to achieve a focused view of the subjects that

are at a particular distance from the camera. High-quality lenses typically

have a calibrated focusing ring that is turned directly or remotely to match

the distance from the camera that is intended to be in focus.

For best precision, the distance is measured from the fi lm plane (just

behind the lens) to the desired point of focus in the shot (oft en precisely to

the eye of the main character). Digital cameras oft en have an automatic focus

feature, in which the camera determines the focusing distance of the subject

at the center of the frame. Th e choice of lens and fi lm stock or sensor used

to record the light aff ect the sharp defi nition of the image, generally referred

to as the quality of resolution in digital photography.

Figure 4-7 Assistant

camera Aegir Gudmundsson

measures focus in the feature

fi lm Of Men and Angels,

directed by William Farley.

(Photo by Gregg Mancuso,

Courtesy of http://www.farleyfi lm.

com)

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