Depth of field is one of the more advanced aspects of photography to master. It is largely controlled by your camera's aperture setting. The aperture is the part of the lens that allows light into the camera.
However, there are other factors that can affect depth of field. Unless you're a seasoned photographer, it can be difficult to achieve the depth of field you are seeking.
That's where DOF Master can help. This depth of field calculator lets you enter information about your camera, its settings and the scene. The calculator will then help you determine the correct depth of field.