Post 2

The story of photography begins long before the first photograph. The camera obscura, Latin for “dark chamber,” was described by the Arab scholar Ibn al-Haytham in the early 11th
century. It was a simple box or room with a small hole in one side: light passing through the hole projected an inverted image of the outside scene onto the opposite wall. Artists
of the Renaissance used it as a drawing aid, but nobody could yet fix the image in place.

The first photograph

That changed in 1826, when the French inventor Nicéphore Niépce coated a pewter plate with bitumen of Judea and exposed it in a camera obscura for around eight hours. The result,
“View from the Window at Le Gras,” is generally considered the world’s oldest surviving photograph. Niépce later partnered with Louis Daguerre, who refined the process after
Niépce’s death. In 1839 the French government announced the daguerreotype process as a gift “free to the world,” and that year is widely treated as the birth year of practical
photography.

The daguerreotype produced a single, unreproducible image on a silvered copper plate. Its rival, the calotype, patented by the Englishman William Henry Fox Talbot in 1841,
produced a paper negative from which many positive prints could be made. This negative-to-positive principle became the foundation of photography for the next 150 years.

Film for everyone

Photography stayed in the hands of professionals and dedicated amateurs until George Eastman introduced the Kodak camera in 1888. It came pre-loaded with a roll of film for 100
exposures, and the company’s slogan captured the revolution: “You press the button, we do the rest.” Owners mailed the whole camera back to the factory, which developed the film
and returned the camera reloaded. In 1900 Eastman followed with the Brownie, a cardboard box camera that sold for one dollar and made photography a genuinely mass hobby.

Color arrived commercially with the Lumière brothers’ Autochrome plates in 1907, which used dyed grains of potato starch as color filters. Practical color film came later:
Kodachrome, introduced by Kodak in 1935, remained in production for 74 years.

The exposure triangle

Every photograph, then and now, is governed by three settings that photographers call the exposure triangle:

• Aperture is the size of the lens opening, measured in f-stops such as f/2.8 or f/16. A lower f-number means a wider opening, more light, and a shallower depth of field.
• Shutter speed is how long the sensor or film is exposed to light, from thousandths of a second to minutes. Fast speeds freeze motion; slow speeds blur it.
• ISO describes sensitivity to light. Higher ISO allows shooting in darker conditions at the cost of more visible noise or grain. Changing any one of the three forces a compensating change in another if the overall exposure is to stay the same. This trade-off is the core discipline of manual photography. The digital turn

The first digital camera was built in 1975 by Steven Sasson, an engineer at Kodak. It weighed 3.6 kilograms, recorded a 0.01 megapixel black-and-white image onto a cassette tape,
and took 23 seconds to capture a single frame. Kodak, fearing damage to its film business, famously declined to pursue the invention aggressively, a decision often cited as one of
the great strategic errors in business history: the company filed for bankruptcy protection in 2012, the same decade smartphone cameras made photography ubiquitous.

Today more photographs are taken every two minutes than were taken in the entire 19th century, and the pocket camera obscura in your phone would have seemed, to Ibn al-Haytham,
like the purest magic.