Meaning of Depth of Field

21.06.2007 Category: Photography Composition
Depth of field is a characteristic of a camera that can be used to enhance the image composition of the photo. Depth of field means the sharp area surrounding the point of focus. The magnitude of the sharp area is affected by several factors: distance between the camera and the subject, focal length and aperture.
The closer the subject to the camera, the more shallow the depth of field.
The longer the focal length, the more shallow the depth of field.
The larger the aperture (smaller the F-number), the more shallow the depth of field.
It is important to understand how to affect the depth of field in order to utilize it in image composition. For example, the subject of the photo can be emphasized by isolating it from its surroundings by using a shallow depth of field. Shallow depth of field is usually used in portraits and large depth of field is usually used in landscape photos.
Shallow Depth of Field

Picture 1. The subject can be isolated from its background by using shallow dept of field.
The dragonfly in picture 1 has been isolated from its chaotic surroundings by using shallow depth of field. By using shallow depth of field the distracting background is blurred and only the dragonfly appears sharp. Viewers eyes concentrate first on the sharp areas of the photo and so the dragonfly gets all the attention.
Large Depth of Field

Picture 2. It's usually a good idea to use great depth