Nikon 1797 Digital Camera User Manual


 
146
SPECIAL FOCUSING SITUATIONS IN AF
Autofocus operation depends on general lighting, subject
contrast and detail, and other technical factors. In rare situations
where autofocus (and manual focus with Electronic Rangefinder)
is not possible, ? blinks telling you to focus manually with
the clear matte field (page 48) or perform autofocus on another
subject located at the same distance.
A. Very dark subject
Focus manually with clear matte field, or
for Single Servo AF, focus on another
brighter subject located at the same
distance, then lock the focus and recom-
pose (pages 70-71). To perform autofo-
cus with Speedlight’s AF-assist illumina-
tor, use a Nikon AF Speedlight (SB-50DX,
SB-29, SB-28/28DX, SB-27, SB-26, SB-
25, SB-23, SB-22s, SB-22 or SB-20).
B. Low-contrast subject
Focus manually with clear matte field, or
for Single Servo AF, focus on another
subject at the same distance but with
more contrast, then lock focus and
recompose (pages 70-71).
C. Strongly backlit subject, bright
subject with shiny surface such as
silver or aluminum, or scene in which
there is a pronounced difference in
brightness.
Use Single Area AF mode and select
subject’s focus area (page 38) or focus
manually with clear matte field.
P400 (E) 02.12.27 6:42 PM Page 146