What does Depth of Field mean in Photography?
Depth of field refers to the distance between the nearest object (or potion of an object) that appears in focus and the farthest object (or portion of an object) that appears to be in focus. Depending on the distance from the lens, the focal length of the lens, and the aperture setting, the depth of field can be as little as a fraction of an inch, or as great as infinity.
What Factors effect depth of field, and how?
The closer the camera is to the subject, the less depth of field. The smaller the aperture (larger number), the greater the depth of field. The wider the lens (shorter focal length) the more depth of field you will get at any given distance from the subject. Also, smaller sensor sizes have greater depth of field, given the same focal length, aperture and camera to subject distance.
When does Depth of Field Matter the Most?
It is important that you have the proper depth of field in any photograph, but how much depth of field you need does vary. When photographing people, animals and insects it is especially important that the depth of field be adequate to allow the eyes to be sharp. Most other parts of living creatures can be less sharp, though it is best to keep the front of the face focused. This can be very difficult when taking macro photos of insects.
For Landscape photography, the entire photograph should be sharp, so you need to use settings that will allow maximum depth of field, and also use the correct focal point.