ISO Tutorial - Luwian iPhone Academy of Photography
In photography, ISO refers to the sensitivity of light in relation to either film or a digital sensor. It is a standard set by the International Standards Organization. When you increase the ISO number, your picture will be brighter.
However, it's important to keep in mind that increasing ISO can also affect your final image quality in terms of graininess, especially when used in combination with high shutter speeds.
Activating the "ISO panel" also activates "Shutter Speed." When "Exposure" is selected, both "ISO" and "Shutter Speed" adjust automatically.