Canon EOS-1D Mark II Digial Советы и техника - Страница 8

AF Modes

One-Shot AF: This mode is intended for use with stationary subjects. It locks focus upon

completion of lens drive, allowing the photographer to recompose if desired. One-Shot

AF is also recommended for maximum performance in extreme low-light situations.

AI Servo AF: This mode is intended for use with moving subjects. It operates

continuously up to the instant of exposure, and it also operates between exposures in

burst mode shooting.

In AI Servo AF, you can tell whether the AF system is tracking the subject by observing

the focus indicator in the viewfinder below the picture area. If the focus indicator does

not light, the system is tracking. If it is blinking rapidly, the system is not tracking.

Please note that this is slightly different from the camera's behavior in One-Shot AF. In

One-Shot, the focus indicator still blinks when the subject can't be focused, but it lights

up continuously when focus has locked.

AF Point Selection

Canon provides two AF point selection methods: Automatic and Manual. The details of

Methods

each method are described below.

Automatic Focusing Point Selection (AFPS): The camera selects a focusing point for

you, choosing from all 45 points. AFPS behavior varies according to your choice of

focusing modes:

• When One-Shot AF is combined with AFPS, the camera typically selects the closest

subject with readable contrast. Since the subject may be large enough to cover several

focusing points simultaneously, the viewfinder's focusing point display may illuminate

as many as 13 points simultaneously. If focus cannot be achieved, the in-focus

indicator below the picture area blinks.

• When AI Servo AF is combined with AFPS, the camera shuts off all focusing points

except the central one until the subject has been identified. Once the camera has

started to track the subject with the center point, all 45 points are activated and the

camera is able to track movement not only towards or away from the camera, but

anywhere the subject moves within the 45-point coverage area.

Manual Focusing Point Selection (MFPS): The photographer selects the desired

focusing point. When the camera is set to its defaults, only one or two focusing points

are used. (To select 2 focusing points at once manually, use the Quick Control Dial to

scroll up or down from the currently selected manual focusing point. When 2 focusing

points are active, the camera evaluates both and selects the one with the most

reliable subject data. This can come in handy when photographing moving subjects.)

The active area around a manually selected focusing point can also be expanded in two

stages via Custom Function 17.

I. CAMERA FEATURES AND OPERATION

See Custom Functions

for details.