What does ISO mean for digital cameras and camcorders?

ISO stands for sensitivity. Sensitivity is a measure of the sensitivity of negative film to light, which is determined by sensitivity measurement and several values measurement. The ISO standard is ISO 6. ISO system closely related to sensitivity is used to measure the sensitivity of digital imaging system.

The calculation formula of ISO is S=0.8/H(S sensitivity, h is exposure). The higher the sensitivity, the lower the requirements for exposure. The photographic speed of ISO 200 film is twice that of ISO 100. In digital cameras, the number of light sources and the value of picture brightness can be changed by adjusting the equivalent sensitivity. Therefore, the sensitivity has also become a value that indirectly controls the brightness of the picture.

Extended data:

Principles of ISO

When providing high sensitivity, it is necessary to provide corresponding gain amplitude, and the corresponding signal must be amplified before outputting the image signal, because the output level of CCD is low, especially in the case of dark ambient light, in order to make the image change quantitatively, the amplifier will increase the gain amplitude according to the corresponding ISO value. In addition, increasing the number of pixels in a given CCD area will make it difficult to maintain sensitivity.

The area of unit pixel decreases and the intensity of incident light weakens. If a higher gain value is called to improve the ISO value, the image quality will deteriorate. Therefore, the manufacturer also provides a solution, that is, when reading the image signal, adding the original image signal stored by CCD can improve the sensitivity relatively. Adding two pixel signals and transmitting them can double the original sensitivity.

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