Moving Images, Understanding Media

130 Moving Images: Making Movies, Understanding Media

motion picture photography in the United

States is 24 frames per second (fps), so

that means a camera running at normal

speed exposes 24 frames each second (for

video or television, it is approximately 30

fps). Since the rotating shutter surface

covers the opening for half of the time that

frame is moving past the camera gate, the

exposure time of each frame is actually

1/48 of a second.

When cinematographers want to shoot

for slow motion or fast motion eff ects, they

can alter the rate of frames per second. For

slow motion, the rate of frames per second

is increased, because when that footage is

played back at the normal rate, it will appear

slow. In other words, normally a fi lm camera will shoot 24 frames per second.

If cinematographers increase it to 48 frames per second, in each second they

will record 48 frames. When the images are played back at the normal rate of

24 frames per second, they will take twice as long to be seen, so what took one

second to happen in reality will take two seconds in the movie. Everything

moves in slow motion. To achieve fast motion, the camera is slowed down,

and then when the moving images are run back at a normal rate, everything

is moving quickly. Th is is also the basis of time-lapse photography.

Let us return to shutter speed. A cinematographer can also have the

fi lm run through the camera at a normal rate of frames per second while the

shutter speed is altered, which causes diff erent optical eff ects depending on

the shutter and its speed. Th ere are a variety of types of shutter design, but

the important issue is its opening in degrees. A high shutter speed causes

motion to take on such sharpness that “the resulting footage takes on the

animated stuttering quality of a fl ip book because there is not enough blur in

the 24 still frames to fool your brain into imagining that you are seeing fl uid

motion,” according to cinematographer Adam Keker. Th is eff ect was used

throughout the groundbreaking D-Day beach landing sequence of Saving

Private Ryan (1998, directed by Steven Spielberg, cinematography by Janusz

Kaminski). Slow shutter speeds can be used to create a blurry, impressionistic

eff ect or they can cause such eff ects as seeing rain falling in daylight when

the drops would have been transparent using a normal shutter speed (of

1/48 of a second).

Factor Three: Sensitivity

Th e third basic parameter aff ecting cinematography—sensitivity—is an

expression of the varying reactions of diff erent types of light-sensitive recording

materials with exposure to light. Film stocks and photography supplies are

materials produced by chemically developed substances and processes, and

f2 f4 f8 f16

• 2 2.8 4 5.6 8 11 16 •• 2 2.8 4 5.6 8 11 16 •• 2 2.8 4 5.6 8 11 16 •

Figure 4-10 Camera, lens, and aperture settings for f/2, f/4,

f/8, and f/16.

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