Olympus E-3 User Manual page 69

simply turns the lens this way or that to determine the point of
the greatest difference between the sensors and, once at that
point, it stops the process. Often, however, it is necessary to
drive the lens just a little bit past the point of sharpest focus
before returning to the point at which the contrast was greatest.
It is for this reason that contrast AF systems are slower and less
reliable than phase detection systems.
Contrast AF, however, has its advantages when focusing in LIVE
VIEW mode and it is fitted to the Olympus E420, E520 and E30
cameras for use with their respective live view modes.
Right, with that behind us, let us look at how you can control the
behaviour of the E-3 AF system.
AF MODES AND TARGET SELECTION
The E-3 offers the following AF modes to suit prevailing
conditions:
S-AF (Single Auto Focus)
•
C-AF (Continuous Auto Focus)
•
MF (Manual Focus)
•
S-AF+MF (Single Auto Focus plus Manual)
•
C-AF+MF (Continuous Auto Focus plus Manual)
•
Now, coupled to the above choices you can also use any of the
following auto focus zone selection methods:
All AF target selection
•
Dynamic single target selection
•
Single target selection
•
Small single target mode
•
S-AF
Single auto focus operates, as the name suggests, by focusing on
a single subject or point and then locking focus on that point.
The shutter is (by default) inhibited from release until the camera
has confirmed focus. Focus lock is indicated (by default) by the
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