DEP is for depth of field auto exposure mode. It allows the camera to decide the
appropriate aperture and focus position to provide enough depth of field to keep two
selected distances sharply in focus. The easiest way to use it is to turn the Command
Dial to DEP, and use the center auto focus sensor, point the camera at the first subject
and press the shutter button half way to autofocus. Let the button up and then point the
same AF sensor on the top of the second subject and press the shutter half way again
to allow the lens to autofocus on the second subject. Then reframe your camera and
take the picture. The camera will select a focus distance between the subject distances,
then select an aperture small enough to keep both subjects in focus and then select a
shutter speed that will provide proper exposure. If you select the same subject distance
twice, the camera will select the widest aperture available to keep depth of field very
shallow. The lens must be set to AF for DEP mode to work and if you are using a zoom
lens, you must not change its zoom setting during the entire procedure. You can also
manually or eye control select the side AF sensors, but I think it just adds confusion.
A blinking aperture indicated that sufficient depth of field (DOF) can not be achieved.
You must focus on subjects that are closer to the same distance apart or use a wider angle
lens.
