Concepts in Photography

Aperture value and the depth of field

You can blur or sharpen the background of a photo by changing the size of the aperture. A large aperture gives your photos a shallow depth of field (DOF). Objects immediately in front of or behind your subject will be blurred, while the subject will be in focus. A small aperture gives your photos a deep depth of field. Objects far in front or far behind your subject and your subject will be in focus.

A photo with a deep DOF

A photo with a shallow DOF

The aperture housing contains several blades. These blades move together and control the amount of light passing through the center of the aperture. The number of blades also affects the shape of light when shooting night scenes. If an aperture has an even number of blades, light divides into an equal number of sections. If the number of blades is odd, the number of sections is double the number of blades.

For example, an aperture with 8 blades divides light into 8 sections and an aperture with 7 blades into 14 sections.

7 blades

8 blades

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Samsung NX1 user manual Aperture value and the depth of field