The origin of shutter speed # Photography Tutorial  

Until the middle 1800 s, “film” materials were not very sensitive to light. In contrast to the instantaneous exposures made on today’s digital sensors, exposures in those early days were made on coated photographic plates and could last several minutes, sometimes an hour or more, even on a sunny day. With such long and imprecise exposure times, shutter mechanisms weren’t even required. To regulate light coming into the camera, a photographer simply removed the lens cap, patiently gazed at his pocket watch until he judged an appropriate time had passed, then—in no great hurry—completed the process by restoring his lens cap. With experience and a bit of luck, enough light had been admitted for a satisfactory exposure. Increasingly light-sensitive coatings and films were developed over the next few decades and photographers began to make shorter and shorter exposures shrinking from minutes, to several seconds, to fractions of a second. This shortening of exposure times had an enormous impact on popularizing photography and created more interest in experimenting with photo subjects far beyond studio portraits and static landscapes. As photographers began to imagine what they could capture with these shorter exposure times, the evolution of a second camera property—smaller size—also helped to ensure many more creative and physical freedoms for photographers. Flexible film joined the parade of improvements, replacing unwieldy and easily-shattered glass plates. And soon after that introduction—with George Eastman of Kodak fame offering to do the complicated business of processing film and printing pictures—everybody wanted a camera. With portable cameras and faster exposure times, photographers liberated their cameras from tripods and wandered the world taking pictures simply by hand holding them. Armed with a camera, even a novice could at long last begin to capture the majesty of a king’s coronation or the magic of an everyday life: picnics at the seashore, children rolling hoops, and horses cantering down country lanes joined the old, stiffly-posed studio portraits in family photo albums. By the 1900 s, photojournalism was born as pictures of soldiers thrusting bayonets, politicians barnstorming from trains, fires ravaging orphanages, earthquakes shaking apart cities, and many other contemporary events made their way into newspapers and magazines. Reasonably fast exposure speeds were part of a great technological breakthrough that enabled many activities of the world to be photographically documented for display, analysis, and discussion. So even 100 years ago, the best answer to the question “What is the primary value of shutter speed?” was not simply: “To admit light into a camera.” By providing a specific amount of light for the sensor and helping to regulate when light is allowed to enter the camera, shutter speed is also an indispensable tool photographers use to creatively interpret their world

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