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Chapter 9 Action and Event Photography
The solution, in these situations, is the use of
electronic flash. The duration of the light burst
from the flash tube is extremely short (between
1/10,000 second and 1/50,000 second), so that the
subject is frozen into stillness.
Using flash to stop motion is most effective
in conditions with low levels of ambient light,
since the subject will be isolated against a dark
background. When the level of ambient light is
fairly high, ghost images can result. Although the
flash serves as the main source of light and stops
subject motion for an instant, the shutter remains
open for 1/60 second (or less, depending on sync
speed). The blurred “ghost” is caused by ambient-
light exposure of the moving subject during the
time the shutter remains open, Figure 9-7. With
older cameras, the blurred ambient light image
is in front of the subject. This occurs because the
flash exposure is made the instant the shutter
opens. The subject continues to move, and is
recorded on the film by ambient light until the
shutter closes. Many newer SLR cameras offer
rear-curtain synchronization that delays the
firing of the flash until the instant before the
second curtain of the focal plane shutter begins
to close. This places the “ghost image” behind the
moving subject for a more natural appearance.
Since sync speeds are higher with most new
cameras, the shutter is open for a shorter
duration, minimizing the ambient-light exposure.
Capturing the Peak of Action
Experienced action photographers, especially
those covering sporting events, are often able to
capture dramatic stop-action photos without the
use of flash or extremely high shutter speeds.
They do so by catching their subject at the
peak of action, an instant when motion slows
dramatically to almost a stop. Probably the
most familiar example of catching the peak of
motion is the image of a pole vaulter or high
jumper who seems to hang in midair, just above
the bar, Figure 9-8. At that instant, the upward
momentum of the athlete is briefly balanced
with the pull of gravity—he or she has stopped
moving upward, but has not yet begun moving
downward. Similar situations occur in most
sports: the football receiver leaping high to snag
a pass, the soccer forward “heading” a ball, the
home-run slugger’s bat meeting the ball, the diver
snapping arrow-straight out of a twist, the rodeo
cowboy being whiplashed atop a bronco or a bull.
See Figure 9-9.
The key to using the peak-of-action technique
effectively is knowing the sport, and sometimes
the individual participant, well enough to
anticipate when action will reach a peak. Some
sports, such as the high jump or basketball,
have action peaks that are fairly regular and
predictable. Others, such as lacrosse or rodeo
Figure 9-7. With rear-curtain flash synchronization,
a “ghost trail” caused by ambient light follows this
swinging crystal pendulum.
Figure 9-8. This jumper has been caught at the peak
of action—the fraction of a second between his body
moving upward and starting to move downward.