“How to make applesauce” A photo where time has stopped

2023.03.12 Sun posted at 12:15 JST

Oscar Holland, CNN

It bursts violently, but is completely stationary. Harold “Doc” Edgerton’s 1964 photograph of a 30-caliber bullet penetrating an apple captures the eye in a detail never seen before. There’s a subdued, sculptural beauty to this photograph of a crumbling apple peel bursting open against a dark blue background.

The photo is widely considered a work of art, but more importantly to the photographer, Edgerton, it is also a feat of electrical engineering. Edgerton, a longtime professor at the Massachusetts Institute of Technology (MIT), used the photo in a lecture known as “How to Make Applesauce.” During his lecture, Edgerton described the pioneering flash technology that helped him photograph the apple.

Edgerton, who died in 1990 at the age of 86, is known as the “father of high-speed photography.” The camera’s shutter speed was too slow to capture the bullet traveling at 2,800 feet per second, but Edgerton’s strobe flash (the predecessor to the modern strobe) produced a momentary burst of light. Because of this, time seemed to stand still in a well-timed photo taken in a dark room. The result is stunning photos, but often comes with tedious cleanup.

“It only takes a third of a microsecond (one millionth of a second) to take a picture,” said J. Kim Vandiver, a former student of Mr. Edgerton and a class assistant, in a video call from Massachusetts. Even though it didn’t take long, he joked that it would take all morning to clean up,” he recalled.

Early camera operators experimented with pyrotechnic “flash powder,” a combination of metal fuel and oxidizer to create a short, bright chemical reaction. was much shorter and easier to control than the light produced by scintillating powder. Edgerton’s breakthrough was more physical than chemical. After arriving at MIT in the 2020s, Edgerton developed a flashlight bulb filled with xenon gas. When this flash bulb is exposed to a high voltage, for a moment electricity rushes between the two electrodes.

Edgerton had developed a microflash that used regular air instead of xenon before taking his now-famous photo of apples. He also captured decades’ worth of famous photographs of hummingbirds in flight, golf clubs hitting balls, and even nuclear bomb explosions. (During World War II, Mr. Edgerton developed a special camera for the U.S. Atomic Energy Commission called the Rapatronic camera. This camera measures the amount of light (exposure) that enters the camera during an explosion. could be adjusted)

But it was a shot of a bullet taken in the 1960s that made some of Edgerton’s photos more memorable. Van Diver, who is still a professor of mechanical engineering at MIT, said the challenge in taking the photo was not to use the flash, but to release the camera at the right time. Human reaction is too slow to shoot manually. So Edgerton used the sound emitted by the subject, the bullet, as a trigger.

“Although it’s not in the picture, there’s a microphone installed just below,” Vandiver said. You can,” he added.

iconic photo

Over the years, Mr. Edgerton and his students shot bananas, balloons and playing cards with rifles. So why did the apple photo become one of Edgerton’s defining photographs, along with the 1957 photo of the splashing milk splash? One of the reasons, Bandiver said, is simplicity. “[The simplicity of it]captures people’s hearts… You can tell what the picture is by just looking at it.” (Bandiver)

Another factor that attracted people to Mr. Edgerton’s photographs was Mr. Edgerton’s artistic eye. Beautifully composed photographs have been republished in newspapers and magazines around the world. More than 100 photographs taken by Mr. Edgerton are now in the collection of the Smithsonian American Art Museum. However, Mr. Edgerton rejected his new title.

“Please don’t treat me like an artist,” Mr. Edgerton said, adding, “I’m an engineer and I only seek facts.”

Mr. Vandiver believes that Mr. Edgerton’s visual experiments have left an artistic legacy, and that they have also advanced the field of photography. gave Edgerton’s method of working with his students lives on at MIT’s Edgerton Center, which was established in his honor in 1992. All students at the center are free to take pictures of bullets, said Van Diver, the center’s director.

“We’re still giving lectures[how to make applesauce]and the students are thinking about taking pictures of strange things,” Vandiver said. He was recently photographed shattering chalk and lipstick with bullets. “Ringo is not interesting anymore,” says Vandiver.