Nikon D3300 - Manual (Page 96)

76 More on Photography
A Getting Good Results with Autofocus
Autofocus does not perform well under the conditions listed below.
The shutter release may be disabled if the camera is unable to focus
under these conditions, or the in-focus indicator (
I) may be displayed
and the camera may sound a beep, allowing the shutter to be released
even when the subject is not in focus. In these cases, focus manually
(
0 83) or use focus lock (0 81) to focus on another subject at the same
distance and then recompose the photograph.
There is little or no contrast between
the subject and the background. The focus point contains areas of
sharply contrasting brightness.
Example : Subject
is the same
color as the
background.
Example : Subject
is half in the
shade.
The focus point contains objects at
different distances from the camera. Background objects appear larger
than the subject.
Example : Subject
is inside a cage.
Example : A
building is in the
frame behind
the subject.
The subject is dominated by regular
geometric patterns. The subject contains many fine
details.
Example : Blinds
or a row of
windows in a
skyscraper.
Example : A field
of flowers or
other subjects
that are small or
lack variation in
brightness.