What Does ISO Mean?

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ISO could stand for any of the following:

  • International Organization for Standardization
  • ISO image file
  • ISO camera settings

ISO – International Organization for Standardization

ISO The International Organization for Standardization or ISO is an independent, non-government organization that aims to set standards for proprietary, commercial and industrial settings. Their members come from 166 different countries but their central office is in Geneva, Switzerland.

Common products that are responsible for standardizing are the ISO image file and ISO camera settings.

ISO image file

ISO The ISO image is the file system that is found on optical discs such as CDs or DVDs. The file system standard was published by the International Organization for Standardization under ISO 9660. This is where the name comes from. Computer files that have the .iso file extension usually indicates the file is an image from a CD or DVD. These files can be written to an optical disc directly or opened using a program such as 7zip or Daemon Tools.

ISO Camera Settings

ISO When speaking about ISO in digital photography, it refers to the measuring the film’s sensitivity to light. This is outlined in ISO 12232 which was published by the International Organization for Standardization (see above).

Values for a film ISO are logarithmic. Consider some possible values:
ISO 100/21°
ISO 200/24°

Usually the logarithmic speed is omitted. This is the value 21° and 24° in the above examples. This results in it being written simply like this:
ISO 100
ISO 200

When one ISO value is twice as much as another ISO value, the higher one is considered twice as sensitive to light as the first value. In digital photography this results in higher ISO settings being lighter than lower ISO settings. In dark settings, it’s common to increase the ISO settings to allow each photo to be more sensitive to light. Keep in mind that raising the ISO settings may result in a lower quality photo that sometimes gives a grainy effect.