Pentax ist d 사용자 설명서

4

When the flash is up in l (single mode) where the subject in dark area, 
pressing the shutter release button halfway will automatically fire the built-
in flash several times, enabling the autofocus to focus on the subject.

The autofocus mechanism is not all-powerful. Subjects which may not 
focus are listed below. These also apply to manual focusing using the 
focus indicator []] in the viewfinder.
For any of these, set the focus mode switch to \ and use the manual 
focus mode to focus on the subject with the aid of the matte field in the 
viewfinder.
a) Extremely low-contrast subject such as a white wall in the focus points 

range.

b) Subjects which don't reflect much light within the focus points range.
c) Subjects that are moving extremely fast.
d) Powerfully reflected light or strong backlight (subjects with extremely 

bright backgrounds).

e) If vertical or horizontal line patterns appear within the focus points range.
f) Multiple subjects in the foreground and background within the focus 

points range.
It may not be in focus even if the focus indicator []] is lit.

g)

You can activate autofocus by pressing the 
AF button and press the shutter button to take 
a picture. 
This functions the same as when you press 
the shutter button halfway down. Once you 
press the AF button during l (Single 
Mode) to adjust the focus, focus lock will 
operate while you hold down the button. 
The camera will continue to adjust the focus while you hold down the 
button in k (Continuous Mode).