From the course: Photography Foundations: Mobile Photography
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Exposure basics: ISO
From the course: Photography Foundations: Mobile Photography
Exposure basics: ISO
- After your sensor is exposed to light, the data from the sensor has to be read, converted to digital information and then analyzed. However, the signals that the sensor detects are very, very faint. So before they can be analyzed, they have to be amplified. This is a tricky process because in addition to detecting the light from your scene, the sensor in your camera also detects other things such as the electronics in your camera, or passing cosmic rays. Those other signals are extremely faint but if you amplify them, they can become visible in your final image. They'll appear as colored splotches or speckled patterns. So it's a tricky balance for a camera manufacturer to find a level of amplification that allows for the necessary image processing, but that doesn't also produce visible noise in the final scene. Now when you buy a roll of film, you choose a particular sensitivity, which is usually referred to as the film's…