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ISO/SENSITIVITY

Definition of Term

  • a system used to measure and adjust how sensitive a digital camera is to light.

Study Guide Resources

  • The ISO setting makes the sensor (formerly film) more or less sensitive to light. The higher the ISO (3200), the more sensitive the camera is to light- which is useful when there is not much light around- like at night time.   
  • However, the higher the ISO, the more "noise" there will be in your image. "Noise" refers to grainy specks that show up on your image. For this reason, it is best to always use the lowest ISO possible, as this will give you the best image quality. Usually this means an ISO of around 100.

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  • ISO affects:
    • -Exposure (makes image sensor more or less sensitive to light)
    • -Image quality (the lower the ISO, the better the quality of your image)
  • NEED TO KNOW:
    • The LOWER the ISO (less sensitive) provides better quality but requires more light to achieve a good exposure.
    • The HIGHER the ISO (more sensitive) provides lower quality but can be used to get a good exposure in low light situations
    • Turning up the ISO is just like turning up the volume on a radio with poor reception. Doing so will not only amplify the desired music, but also the undesired hiss and crackle or noise.
    • The unmagnified crops below of prosumer digital camera images show high levels of color noise at higher ISO sensitivities. Noise is usually most visible in the red and blue channels.This applies to both still and video cameras.
    • Improvements in sensor technology are steadily reducing the noise levels at higer ISOs, especially on more expensive pro camera

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