The Mystery of the Depth of Field!

Depth of Field or DOF is used to describe a how deep the field of sharpness in an image is.

For example if you have a few objects lying randomly on the floor, at different distances in each direction.

Now a shallow depth of field will blur everything except everything that lies in the vertical plane of the point of focus.  A deeper depth of field will increase the field of sharp vision, thus having a larger DOF.

D-SLR cameras have a very shallow depth of field, this can be controlled very well by decreasing the Aperture size, i.e. larger F number. Again for clarification (f/1.8 is larger aperture than f/10)

Below are three sample images that illustrate DOF:

A: f/1.8

1: The lens is set at MAX aperture i.e. f/1.8 and thus allowing in the most light possible, but also reducing the depth of field to only a few millimeters. Focus point: Green Cylinder.  The small green cylinder and the white cube are almost in the same vertical plane, watch them in the next image.

A: f/2.8

2. The aperture is now set at f/2.8, this increases the DOF by a centimeter, the objects in the foreground and the background are still out of focus/not sharp.

A: f/13

3. The increase the depth of field by a few feet the aperture is now set at f/13, now every piece in the image is razor-sharp and even the distant objects like the foot of the couch and a flip-flop is visible sharp to a certain extent.

Thus to improve on the depth of field the aperture should be decreased, although to prevent blur from camera shake, ISO should be increased to increase shutter speed.

USE of Shallow DOF: Portrait, Wildlife, Sports, Macro

USE of Deeper DOF: Landscapes, Cityscapes, all situation where sharpness of the entire field is wanted.

Hope that helped, ask anything as always. 🙂