From the course: Photography Foundations: Exposure (part 1)

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ISO

ISO

From the course: Photography Foundations: Exposure (part 1)

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ISO

- Shutter speed and aperture are physical mechanisms that allow you to control how much light strikes the focal plane, the place where the image sensor or piece of film sits in your camera. In the very early days of photography, shutter speeds were usually always very long, usually minutes. 30 seconds was considered a short exposure. That's why people in portraits in the 19th century often look so dour. They weren't necessarily in a foul mood, they just had to sit very still for a long time. So, they adopted neutral expressions that were easy to hold. One reason that shutter speeds were so long then, is that the films of the day were not very light sensitive. It took a long time for them to gather enough light to create an image. As film technology and lens technology improved, and the light gathering speeds of film increased, shutter speeds could get shorter. We measure the light gathering speed of a film using a scale called ISO. Now, if you come from way back in the film days, you…

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