This document discusses aperture and depth of field in photography. It explains that aperture, which is the size of the lens opening, impacts depth of field, with smaller apertures resulting in a larger depth of field and more of the image being in focus, while larger apertures produce shallower depth of field focusing mainly on close objects. Landscape photographers tend to use small apertures to keep more of the scene in focus, while portrait photographers often employ large apertures to focus on subjects and blur backgrounds.

1. Photography 101: Aperture and
Depth of Field
By James P Knell

2. Introduction
• As the chairman of the SIMA umbrella of
companies, James P. Knell plays an integral role in
the management of the SIMA Management
Corporation and the SIMA Corporation. Outside of
his work with SIMA, James P. Knell is an avid
photographer.
In the world of photography, aperture represents
one of the most important aspects of a photograph.
Defined simply as the size of the opening in the lens,
aperture has a major impact on the depth of field in
a photograph.

3. Aperture and Depth of Field
• As a general rule, small apertures produce a large
depth of field, meaning that the majority of an
image will be in focus. Conversely, a large aperture
will result in a photograph with only close objects in
focus. Photographers can manipulate this
phenomenon in an almost infinite number of ways.
Landscape photographers typically prefer to capture
as much of a scene as possible with small apertures,
while portrait photographers often use large
apertures to place the focus on their subjects instead
of the background.