Samsung NX100 ユーザーズマニュアル

Concepts in Photography

How the aperture setting, shutter speed, 
and ISO sensitivity control exposure

The aperture setting, shutter speed, and ISO sensitivity are closely 
interconnected in photography. The aperture setting controls the 
opening that regulates the light that enters the camera, while the shutter 
speed determines the length of time that light is allowed to enter. 
ISO sensitivity determines the speed at which the film reacts to light. 
Together, these three aspects are described as the triangle of exposure.

A change in shutter speed, aperture value, or ISO sensitivity can be 
offset by adjustments to the others to maintain the amount of light. 
The results, however, change according to the settings. For example, 
shutter speed is useful in expressing movement, aperture can control 
the depth of field, and ISO sensitivity can control the graininess of a 
photo.

Shutter speed

Fast speed  
= less light
Slow speed  
= more light

Fast = still
Slow = blurry

Aperture

Wide aperture  
= more light
Narrow aperture  
= less light

Wide = small depth of field
Narrow = large depth of field

ISO sensitivity

High sensitivity  
= more sensitive to light
Low sensitivity  
= less sensitive to light

High = more grainy 
Low = less grainy