GS Photography: Depth of Field.

The Depth of Field of a lens is the zone of sharpness. This zone extends in the front and back of the subject in which the image is sharp. The DOF of any lens depends upon the focal length of the lens, the relative aperture and the distance between the object and the lens....DOF increases:

a) the distance between the object and the lens increases;

b) the focal length of the lens decreases;

c) the aperture is stopped down.

2) Previously in cameras using film, DOF scale was given on the lens for each aperture setting....But the dCams do not have the scale. The DOF plays a very important part in picture making. With the increase/decrease of DOF the character of the picture is entirely changed. The DOF is maximum when the aperture is minimum and it is minimum when the aperture is full open. Therefore by decreasing the DOF, unwanted things in the foreground or background can be thrown out of focus. So isolation of any subject is possible. A 3D effect can be created; illusion of different plains can be achieved and above all, a picture can be softened.

3) On the other hand if the DOF is increased (using small aperture), everything in the background or foreground including the main subject will be sharp and in focus. The picture will have good contrast and sharpness.Therefore before you shoot pictures, decide the effect you want to get, then accordingly select the aperture..

The use of DOF is an essential tool in the hands of a creative photographer.

4) IN THE PICTURE above, I used wide aperture to soften the flowers and get the desired DOF in the middle two flowers...Thus the foreground flowers and bg flowers are out of focus...By using the wide aperture, the attention or the eyes of the viewer are stopping on the middle flowers and the foreground and background flowers are out of focus besides, the distant background has gone total OOF.