Panasonic NV-S99A - Manual (Page 31)

■ The Auto Focus Mechanism of this Movie Camera
• In Movie Cameras, one of the following two methods is generally used:
1) Infrared Focusing: The recording distance is calculated and adjusted based on the time it takes for an
infrared signal emitted from the front of the Movie Camera to be bounced off the subject and received back
by a sensor on the Movie Camera.
2) Camera-Internal Electronic Focusing: The focus is adjusted based exclusively on the image received by the
Movie Camera and the resulting picture signal.
This Panasonic Movie Camera employs the Internal Electronic Focusing Method.
•As shown in Fig. 1 on the left page, when you aim the Movie Camera at the subject you want to record, the
microprocessor moves the lens little by little based on the information about vertical contours of the subject in
the picture signal. At the point where the vertical contours of the subject become sharpest, it judges that the
subject is in focus and stops the lens. (See Fig. 2.)
• Special Characteristics of the Mo v:e Camera’s Automatic Focus Adjustment Mode
(A) It adjusts the focus for sharpest vertical lines.
(B) It ad;US'S the focus on parts of the subject with strong contrast.
(C) ¡1 adjusts the focus only on the centre part of the picture on the viewfinder screen. {The area where the
subject is in focus is much smaller than the TV screen, as shown in the Fig. 3.)
Unlike the human eyes, however, the Movie Camera’s Auto Focus System cannot change the focus from a
distant to a close subject without any delay. Therefore, use the Manual Focus Mode when you are going to
record the following types of subjects or in the following kinds of places:
Subjects with Shiny Surfaces
or Much Light Reflection
As the Movie Camera adjusts the
focus on the objects with shiny
surfaces or much light reflection,
the subject may go out of focus.
•The subject may be out of focus
when it is recorded at the
seaside in the evening, under
firework iliumination or when
special kinds of lights are used.
Fast-moving Subjects
As the lens is moved
mechanically, it cannot follow
fast-moving subjects without
delay.
•Subjects like a quickly and
abruptly moving children may
temporarily go out of focus.
Subjects with Weak Contrast
As the Movie Camera adjusts the
focus based on vertical contours
in the picture, subjects with little
contrast may be out of focus.
•When recording a flat white
wall, for example, the Movie
Camera has no information by
which it can adjust the focus
correctly.
Subjects with a Part of It Near
the Movie Camera and Another
Part Far Away from It
As the focus is adjusted on the
centre part of the image, it is
difficult to bring the distant part of
the subject in focus.
•When you want to record a
person with a distant mountain
behind, it is not possible to
focus on both.
Subjects Behind Moving
Objects
As the focus is adjusted on the
person or object that passes
between the Movie Camera and
the subject, the subject
temporarily go out of focus.
•When recording a subject
across a street on which cars
are running, the subjects may
go in and out of focus.
Subjects with Dark Surfaces
If the amount of light entering the
lens is greatly reduced, the Movie
Camera has very little information
by which to adjust the focus.
•When recording persons in dark
surroundings, precise focusing
may not be possible.
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•Precise focusing may also not be possible for subjects that have no vertical contours or are behind glass
covered with dirt, dust or water droplets.
• Finger print marks on lens may cause focus not to operate clearly. When at wide angle the Movie Camera
may attempt to focus onto the finger prints (treating them as a MACRO Subject). Check and clean the lens
correctly.
• If recording in a moving vehicle focus accuracy may be impaired due to the following:
a) Dirt or water droplets on the car windows and recording through glass may change the focus point
b) Scenery changing too quickly, no time for the camera to adjust focus
c) Distance between subject and camera always changing
We suggest you use Manual Focus. Please refer to pages 28-29 “Recording in Manual Focus Mode” in your
operating instructions.
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