Moving Images, Understanding Media

126 Moving Images: Making Movies, Understanding Media

Fundamentals of Cinematography

Th e camera, lens, and recording medium are used to capture the light

of the scene that they are facing. Let us examine the key factors that determine

the parameters and qualities of the images that are recorded by

the camera.

The Lens

Th e lens mounted on the camera is a key instrument in determining the frame

the fi lmmakers wish to photograph. Th e relative size of the frame in relation

to the fi eld of view in front of the camera is aff ected by the focal length of the

lens. Focal length is the measurement in millimeters that indicates the type

of a particular lens, such as 16mm, 25mm, 50mm, or 150mm. Focal length

is measured inside the body of the lens: It is the length from the rear nodal

point of the lens (where light is being sent back by refraction) to the fi lm

plane when the lens is focused at infi nity. Lenses with small focal lengths

are referred to as wide-angle, while large focal length lenses are referred to

as long-focus, including telephoto lenses. A lens that duplicates the general

perspective of the human eye and falls between wide and long lenses is called

a normal lens.

Essentially, focal length is what determines what kind of shot will

be photographed. Before the invention of the zoom lens, all lenses were

prime lenses, which have a fixed focal length (such as 25mm, 50mm,

150mm, and so forth) and which are still used today because of their

extreme sharpness and aperture range. With a zoom lens such as the one

found on consumer digital cameras, you can change your focal length

Figure 4-6 Image

photographed with a long

lens: Note that the trees and

fence at left and right and the

people in the background

are out of focus, while the

principal actor is in focus.

From Side Streets directed by

Tony Gerber, photo by Seth

Rubin. (Courtesy Market Road

Films)

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