Several factors that influence depth of field:
First, by lens aperture or F value influence. Lens aperture (aperture refers to the size of the circular aperture), the aperture are used to control the amount of light into the camera, aperture is larger, the more light into the camera, The smaller aperture, into the camera's ray is less. Aperture size can also control of the depth of field, namely aperture is bigger, the depth of the smaller aperture smaller, the greater the depth of field.
Lens aperture size is expressed with F value, lens aperture, the greater the F values smaller.
1, the smaller aperture (F value bigger), the depth of field.
2, aperture the larger (F values smaller), the smaller the depth of field.
Second, by focusing on distance or cameras to be taken body distance influence.
In the same aperture, focus distance (focus) more far, depth of field bigger, The camera can be adjusted for the farther away from the body, depth, If the camera is nearer, preview will be smaller.
Third, the shorter the focal length of the lens, the depth of field, The longer the focal length of the lens, the smaller the depth of field.
Depth of field use skill:
Obtaining the minimal dof: the maximum possible shorten the perturbation aperture + from + long-focal-length lens
Maximum dof: minimum aperture + shortest focal length lens + super focal length focus