In analog photography the ISO value indicates the film’s sensitivity: the higher this value is, the less light is required to shoot the picture. This means that photographers must think beforehand about which film they are going to use and its sensitivity. Their choice is dependent on the prevailing light conditions. This brings us to one of the key benefits of digital photography: the ISO setting can be simply and constantly modified. In digital photography the ISO value represents the light sensitivity of the image sensor that replaces the analog film in this case.

Sensor sensitivity and ISO

A good sensor is vital for enabling you to shoot good digiscoping pictures. The image sensor’s light sensitivity is expressed by the ISO number. The higher this number is, the more sensitive the image sensor is and the brighter the pictures that you can take. Depending on the sensor’s quality, an increase in image noise also occurs with very high ISO values. The highest possible ISO value should be set for good digiscoping shots, but which still prevents image noise from being generated.

The practical ISO value for each of the camera types, determined by the different sensor sizes, lies roughly within the following range of values:
Compact cameras: ISO: ~ up to 400
System cameras: ISO: ~ up to 1000
DSLR cameras: ISO: ~ 1000 – 3200