The distance between the closest and furthest points in an image that are in ‘acceptable focus’.

In every picture there is a certain area of your image in front of, and behind the subject that will appear in focus.

This zone will vary from photo to photo. Some images may have very small zones of focus which is called shallow depth of field. Others may have a very large zone of focus which is called deepdepth of field. Three main factors that will affect how you control thedepth of field of your images are: aperture (f-stop), distance from the subject to the camera, and focal length of the lens on your camera.