5- freeze frames-stopping time
For most people, the arc of their golf swing or tennis stroke is an abstract image, something that happens much too fast for the unaided eye to see. Fortunately, modern athletes have a special tool available— StToMotion™—with which to obtain and study an actual, visible record of their movements. But StroMotion™ is not a brand new concept— in fact it's an old idea newly linked to digital video and computer software. StroMotion™ uses processes and technology developed by photographic pioneers such as Eadweard Muybridge, who conducted the first photographic sequential motion studies, and Harold Edgerton, inventor of the strobe light, which seems to stop even the speediest objects—like bullets—in transit.
In 1872, Leland Stanford—the soon-to-be Governor of California who was also a businessman, horse lover, racetrack owner, and later founder of Stanford University— encountered this commonly debated question of the time: whether during a horse's gallop all four hooves were ever off the ground at the same time. This was called "unsupported transit," and Stanford took it upon himself to settle this popular debate scientifically. He hired a well-known British photographer named Eadweard Muybridge, then working in San Francisco, to get the answer.
By 1878, Muybridge had successfully photographed a horse in fast motion using a series of fifty cameras. The cameras were arranged along a track parallel to the horse's, and each of the camera shutters was triggered by electronic timers developed specifically for the project. The resulting series of photos proved that the hooves do all leave the ground at the same time—although not with the legs fully extended forward and back, as artists of the day had imagined, but rather at the moment when all the hooves are tucked under the horse, as it switches from "pulling" from the front legs to "pushing" from the back legs.
Muybridge continued to use this technique to photograph human beings and animals in order to "freeze" and study their motion. He made sequential motion studies of athletes in a wide variety of sports and additional studies of everyday people performing mundane movements like walking down stairs. Muybridge's work helped inaugurate the modern science of biomechanics, the research and analysis of the mechanics of living organisms.
Furthermore, when a viewer flips rapidly through a sequence of Muybridge's pictures, it appears to the eye that the original motion has been restored. Viewers appreciated these images for reasons of both science and entertainment, and inventors like Thomas Edison were inspired to work harder on the creation of a motion picture process. Hence Muybridge is considered to have been a crucial figure in the development of movies.
Muybridge showed that the value of a sequence of photographs could be greater than that of any single image, a lesson that was later applied in photojoumalism as well as biomechanics. But after Muybridge, inventors persisted in seeking ways to photograph faster and faster motion, and eventually they came back to the stroboscope.
A stroboscope, also known as a strobe, is an instrument used to make a fast-moving object appear to be slow-moving or stationary. It is mainly employed in industry for the study of the motion of objects, such as rotating machine parts or vibrating strings.
The stroboscope was designed by Joseph Plateau of Belgium in 1832. In its simplest form, it is a rotating disc with evenly spaced small openings cut into it. It is placed between the observer and the moving object and rotates to alternately block and reveal the object. When the speed of the disc is adjusted so that it becomes synchronized with the object's movement, the object seems to slow and stop. The illusion is commonly known as the "stroboscopic effect."
In 1931, almost exactly one hundred years after Plateau, an engineering professor at the Massachusetts Institute of Technology named Harold Edgerton combined the stroboscope and the camera. He created an electronic version of the strobe in which the rotating disc was replaced by a special lamp. The lamp emits brief and rapid flashes of light. The frequency of the flash is adjusted so that it is a fraction of the object's speed. At this point, the object appears to be stationary.
Although his original goal was to display and study the stresses on moving machine parts otherwise invisible to the naked eye, Edgerton later used very short flashes of light as a means of producing dramatic still photographs of fast-moving objects in transit, such as bullets in flight, hovering hummingbirds, and falling milk drops splashing into a bowl. His camera had no shutter. The film was pulled through continuously as in motion picture cameras— but at much higher speeds—and exposed by a stroboscopic flash lasting 1/1,000,000 of a second or less.
Edgerton's invention was the basis for the built-in light flash found in nearly all cameras today. Strobes are also popular as a lighting effect in nightclubs, where they create the appearance of dancing in slow motion. Other common uses are in alarm systems, theatrical lighting (for example, to simulate lightning), and as high-visibility navigation lights.
In medicine, stroboscopes are used to view the vocal cords. Both the strobe and the camera are placed inside the patient's neck using a procedure called endoscopy. The patient then hums or speaks into a microphone, which in turn activates the stroboscope. Doctors can see the movement of the vocal cords and diagnose problems.
Strobe technology has also been instrumental in the development of underwater scanning technology—useful in searching the sea bottom for shipwrecks—and is valuable in photographing creatures living in the darkest depths of the ocean. Edgerton worked with the undersea explorer Jacques Cousteau, providing him with underwater stroboscopes.
In addition to having the science, engineering, and business skills to advance strobe lighting commercially, Edgerton is equally appreciated for his visual flair. Many of the dramatic images he created for science are now found in art museums worldwide. In Edgerton's strobe work. science and art encounter one another and find that in some way they serve the same need for exactitude—a goal shared by the athletes who use video StroMotion™ today to improve their competitive performance.
