Kodak DCS Pro SLR/n manual Depth of Field and Focus Tracking

Focusing

Depth of Field and Focus Tracking

Your camera is equipped with autofocus where focusing is automatically executed. Basics of the relationship between focus, depth of field, and focus tracking are explained in this section.

Depth of Field	When focusing, consider depth of field. Depth of field is the zone of
	sharpest focus in front of and behind the subject on which the lens is
	focused. Depth of field varies according to shooting distance, focal length,
	and especially aperture.
	Smaller apertures (larger f-numbers) produce a deeper depth of field
	where the background and foreground become sharper. Larger apertures
	(smaller f-numbers) produce a shallower depth of field where the
	background becomes blurred.
	Similarly, shorter shooting distance or longer focal length produce a
	shallower depth of field, and longer shooting distance or shorter focal
	length produce a deeper depth of field. Note that depth of field tends to be
	shallower in front of the subject in focus and deeper behind the subject.
	NOTE: You can confirm the depth of field with the Depth of Field Preview
	button (see page 2-21).
Focus Tracking	Your camera automatically switches to focus tracking when a moving
	subject is detected under the following conditions:
	• The Focus Mode selector is set to Single Servo AF (S) or Continuous
	Servo AF (C) and you lightly press the Shutter Release button.
	• You lightly press the Shutter Release button or press and hold
	when the AE--L/AF-L Button Custom Setting is set to Start (see page 5-2).
	Focus tracking lets the camera analyze the speed of the moving subject and
	obtain correct focus by anticipating the subject’s position and driving the
	lens to that position at the exact moment of exposure.
	In Single Servo AF, Focus Tracking is activated with a subject that has been
	moving before the focus detection. Focus locks when the subject stops
	moving and the focus mode indicator	appears in the viewfinder.

In Continuous Servo AF, the camera continues to track the subject and focus is not locked. Tracking occurs even if a subject starts moving in the middle of focus detection.

8-10 April 29, 2004