HIGH SPEED PHOTOGRAPHY
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Photography
gained the interest of many scientists and artists from its inception.
Scientists have used photography to record and study movements, such as
Eadweard Muybridge’s study of human and animal locomotion in 1887. Artists
are equally interested by these aspects but also try to explore avenues
other than the photo-mechanical representation of reality, such as the
pictorialist movement. Military, police, and security forces use
photography for surveil-lance, recognition and data storage. Photography is
used by amateurs to preserve memories, to capture special moments, to tell
stories, to send messages, and as a source of entertainment. Various
technological improvements and techniques have even allowed for visualising
events that are too fast or too slow for the human eye.
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One of such techniques is
called fast motion or professionally known as time-lapse. Time-lapse
photography is the perfect technique for capturing events and movements in
the natural world that occur over a timescale too slow for human perception
to follow. The life cycle of a mushroom, for example, is incredibly subtle
to the human eye. To present its growth in front of audiences, the
principle applied is a simple one: a series of photographs are taken and
used in sequence to make a moving-image film, but since each frame is taken
with a lapse at a time interval between each shot, when played back at
normal speed, a continuous action is produced and it appears to speed up.
Put simply: we are shrinking time. Objects and events that: would normally
take several minutes, days or even months can be viewed to completion in
seconds having been sped up by factors of tens to millions.
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Another
commonly used technique is high-speed photography, the science of taking
pictures of very fast phenomena. High-speed photography can be considered
to be the opposite of time-lapse photography. One of the many applications
is found in biology studies to study birds, bats and even spider silk.
Imagine a hummingbird hovering almost completely still in the air, feeding
on nectar. With every flap, its wings bend, flex and change shape. These
subtle movements precisely control the lift its wings generate, making it
an excellent hoverer. But a hummingbird flaps its wings up to 80 times
every second. The only way to truly capture this motion is with cameras
that will, in effect, slow down time. To do this, a greater length of film
is taken at a high sampling frequency or frame rate, which is much faster
than it will be projected on screen. When replayed at normal speed, time
appears to be slowed down proportionately. That is why high-speed cameras
have become such a mainstay of biology.
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In common usage, high-speed
photography can also refer to the use of high-speed cameras that the
photograph itself may be taken in a way as to appear to freeze the motion,
especially to reduce motion blur. It requires a sensor with good
sensitivity and either a very good shut-tering system or a very fast strobe
light. The recent National Geographic footage—captured last summer during
an intensive three-day shoot at the Cincinnati Zoo—is unprecedented in its
clarity and detail. “I’ve watched cheetahs run for 30 years,” said Cathryn
Milker, founder of the zoo’s Cat Ambassador Program. “But I saw things in
that super slow-motion video that I’ve never seen before.” The slow-motion
video is entrancing. Every part of the sprinting cat’s anatomy—supple
limbs, rippling muscles, hyperflexible spine—works together in a sym-phony
of speed, revealing the fluid grace of the world’s fastest land animal.
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But things
can’t get any more complicated in the case of filming a frog catching its
prey. Frogs can snatch up prey in a few thousandths of a second—striking
out with elastic tongues. Biologists would love to see how a frog’s tongue
roll out, adhere to prey, and roll back into the frog’s mouth. But this all
happened too fast, 50 times faster than an eye blink. So natu-rally people thought
of using high-speed camera to capture this fantastic movement in slow
motion. Yet one problem still remains—viewers would be bored if they watch
the frog swim in slow motion for too long. So how to skip this? The
solution is a simple one—adjust the playback speed, which is also called by
some the film speed adjustment. The film will origi-nally be shot at a high
frame (often 300 frames per second, because it can be converted to much
lower frame rates without major issues), but at later editing stage this
high frame rate will only be preserved for the prey catching part, while
the swimming part will be converted to the normal speed at 24 frames per
second. Voila, the scientists can now sit back and enjoy watching without
having to go through the pain of waiting.
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Sometimes taking a good
picture or shooting a good film is not all about technology, but patience,
like in the case of bat. Bats are small, dark-colored; they fly fast and
are active only at night. To capture bats on film, one must use some type
of camera-tripping device. Photog-raphers or film-makers often place camera
near the bat cave, on the path of the flying bats. The camera must be
hard-wired with a tripping device so that every time a bat breaks the
tripping beam the camera fires and it will keep doing so through the night
until the camera’s battery runs out. Though highly-advanced tripping device
can now allow for unmanned shooting, it still may take several nights to
get a truly high quality film.
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Is it
science? Is it art? Since the technique was first pioneered around two
hundred years ago, photography has developed to a state where it is almost
unrecognisable. Some people would even say the future of photography will
be nothing like how we imagine it. No matter what future it may hold,
photography will continue to develop as it has been repeatedly
demon-strated in many aspects of our life that “a picture is worth a
thousand words.”
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Questions 27-30
Look at the following organisms
(Questions 27-30) and the list of features below.
Match each organism with the
correct feature, A-D.
Write the correct letter, A-D,
in boxes 27-30 on your answer sheet.
27. Mushroom
28.
Hummingbird
29. Frog
30. Bat
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A too fast to be perceived
B film at the place where the
animal will pass
C too slow to be visible to human
eyes
D adjust the filming speed to
make it interesting
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Questions 31-35
Complete the summary below.
Choose NO MORE THAN THREE
WORDS from the passage for each answer.
Write your answers in boxes 31-35
on your answer sheet.
Fast motion (professionally known as time-lapse photography) and slow
motion (or high-speed photography) are two commonest techniques of
photography. To present before audiences something that occurs naturally
slow, photographers take each picture at a 31 ______________ before another
picture. When these pictures are finally shown on screen in sequence at a
normal motion picture rate, audiences see a 32 ______________ that is
faster than what it naturally is. This technique can make audiences feel as
if 33 ______________ is shrunk. On the other hand, to demonstrate how fast
things move, the movement is exposed on a 34 ______________ of film, and
then projected on screen at normal playback speed. This makes viewers feel
time is 35 ______________.
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Questions 36-40
Reading Passage
3 has seven paragraphs, A-G.
Which paragraph contains the
following information?
Write the correct letter, A-G,
in boxes 36-40 on your answer sheet.
36 a description of
photography’s application in various fields
37 a reference to why high-speed
photography has a significant role in biology
38 a traditional wisdom that
assures readers of the prospects of photography
39 a reference to how film
is processed before final release
40 a description of filming
shooting without human effort
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