Olympus OM77AF Instructions Manual page 57

Subject difficult for autofocus
Although the OM77AF can focus in almost any
situation, there are certain conditions, illustrated
below, in which it may be impossible to obtain
correct focus. A red LED in the viewfinder will
usually indicate these conditions, however, in
situations , and
viewfinder may illuminate even though the lens is
incorrectly focused. In any of these situations, you
can try focusing on a subject at a similar distance
and then, using the Focus Lock (pages 30 — 31),
, the green LED in the
recompose your picture, or you can use the Power
Focus mode (pages 24 — 26) to focus manually.
Subject without vertical lines.
Subject without contrast.
Rapidly moving subjects.
Two subjects within the focusing frame at
different distances.
Excessively bright light at the center of the
focusing frame.
Subject with repeated pattern.
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