I

nitially depth of field seems to be an

easy concept to understand:

A small lens aperture increases the area in a

picture that’s in focus in front of and behind

the subject on which you’ve focused.

The truth is, however, depth of field is com-

plex and it requires years of experience to fully

understand how it behaves. DOF is not just a

function of lens aperture; it is also influenced

by three other factors. Let me define these for

you, and then I’ll relate this information to the

real world. For most of you, this is review. But

bear with me because you might pick up a tip

or two that will be very relevant to your picture

taking.

1. A large lens aperture (like f/2.8) means shal-

low depth of field, and a small aperture (like

f/22) translates to extensive depth of field.

2. A telephoto lens produces shallow depth of

field, while a wide angle lens gives you imag-

es with tremendous DOF. The longer the lens

(like 400mm), the less DOF; the shorter the lens

(like 16mm), the greater the focus throughout

the photograph.

DEPTH OF FIELD CONFUSION