What is depth of field?

DOF is the zone of acceptable sharpness within a photo that will appear in 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 'deep depth' of field. Three main factors that will affect how you control the depth 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.

Depth of field diagram

In this picture below to the right there is a gradual focus change within the picture with a very narrow depth of field, allowing the photo to be in focus of one particular object. However to the left there is a much bigger depth of field stretching to infinity, allowing the backdrop to stay focused in detail at the same time.


I decided to have a go with the method in a few of my photos, and so walked around school experimenting with it, these were my results:

I thought that messing around with the lighting would allow significantly for the viewer to notice what the focal point would be, and to my opinion I think that it worked.