Sony DSLR-A100K - alpha; Digital Single Lens Reflex Camera Brochure & Specs page 19

Taking your best shot
CAMERA CONTROL
Focus Sony focus
features
With all but the most basic cameras, image
sharpness depends on adjusting the lens
according to the distance to the subject. This,
Taking advantage of the BIONZ
circuit, Sony cameras accurately recognize
of course, is focus.
– and focus on – the human face.
During manual focus, you can consult
the image in the LCD monitor, electronic
viewfinder or through-the-lens optical
BIONZ ™ processor solves this problem with
viewfinder. You then adjust the focus until
Face Detection. As you shoot, the Face
the subject is clear. On auto focus cameras,
Detection function actually analyzes the
you can simply point and shoot.
data that make up your digital picture. In
this way, Face Detection can identify and
Typical auto focus (AF) systems detect the
track up to eight faces at a time. Then the
picture information coming off the image
camera automatically adjusts for optimum
sensor. When contrast in the image is highest,
focus, exposure, flash and even white balance
the subject is in focus. When contrast is low,
on the faces themselves. The result is far more
the image is out of focus. In this way, AF
"good" pictures, far fewer rejects and re-takes.
systems can work quickly and automatically.
AF systems generally work quite well.
But they can be thrown off by some
tricky circumstances.
• The challenge of darkness.
Unfortunately, auto focus can run
into trouble in low light, when the
camera can't "see" contrast coming
off the image sensor.
• The challenge of composition.
Sony solves common focus problems with Face Detection technology. (Sample photos for illustration purposes.)
Most AF systems look towards the
center of the frame. Unfortunately, if
your subject is away from the center,
the camera could well be focusing
on the wrong thing.
• The challenge of subject motion.
If you're shooting kids, pets or sports,
your subject can unexpectedly move
toward or away from the camera. This
means the camera-to-subject distance
is changing from moment to moment –
another challenge for AF systems.
For these reasons, Sony has developed
an array of powerful features for focus
While conventional focus (left) becomes very hit-or-miss in low light, our AF Illuminator (right) is right on target. (Sample
illumination, processing and control.
photos for illustration purposes.)
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For the complete story on Face Detection
and the BIONZ processor, please turn to
page 26.
AF Illuminator
Face Detection
Accurate focusing, even in low light.
™ integrated
Auto focus can run into trouble in low light,
when the camera can't "see" contrast coming
off the image sensor. That's why Sony offers
Even a simple snapshot can trip
AF Illuminator. The camera throws a special
up the automatic focus on a
light on the subject prior to the shot, so the
conventional camera. Sony's
camera can "see" the subject's contrast. You
get accurate focusing, even in low light.
Multi-Point Auto Focus
Automatically finds the focus, even when
your subject isn't in the center of the frame.
INCORRECT FOCUS CORRECT FOCUS
CAMERA CONTROL
If the subject is off-center, cameras with a single focus point (left) tend to focus on the background. Sony Multi-Point AF (right) automatically brings the subjects into focus. (Sample
photos for illustration purposes.)
With the Flexible Spot AF of the DSC-H7, H9, and N2, you can frame the shot first, then
use the camera controls to select the focus point. (Sample photo for illustration purposes.)
Simple cameras simply focus on whatever is To accommodate the full range of shooting
in the middle of the frame. But when you're situations, Multi-Point AF also includes
taking a picture of two people, the center switchable modes like Center AF, which
of the frame often shows the background – uses only the center area, Spot AF,
the wrong place to focus! In other cases, which uses only a tiny spot and Focus
you'll get a more creative shot when the Lock, which enables you to focus first, and
subject is off center. For these reasons, then frame the shot any way you want.
Sony developed Multi-Point Auto Focus.
Some Sony cameras use a five-point system,
Advanced Sports Shooting
automatically selecting the right focus
Mode Auto Focus
points based on your composition. Cameras
equipped with the BIONZ ™ processor use
Predictive auto focus knows not only
a nine-point system. So you get critically
where your little soccer player is,
accurate focusing under a wider range
but where she's going.
of conditions.
To keep up with fast action, the DSC-H7
and H9 15x zoom cameras incorporate a
special version of Continuous AF (discussed
in the Selectable AF section below). Instead
of simply "keeping up" with your moving
subject, the camera actually predicts where
the subject will go in the interval between
shutter release and image capture. This can
be a key advantage in sports, especially if
the subject is moving towards you.
A super-fast 1/4000 second shutter speed
helps to freeze the action on even the
fastest midfielder.
Selectable AF
Perfect for unpredictable sports and fast-
moving subjects, because you can choose
a more responsive focus mode.
Single Shot Auto Focus "locks" onto the
subject as soon as you press the shutter
half-way, which can be a problem when
there's plenty of relative motion between
the subject and the camera.
• Single Shot AF is ideal for subjects
that are standing still. The Auto Focus
process doesn't begin until you press
the shutter halfway.
• Monitor AF speeds the shot, an
important advantage in sports
Continued on page 36.
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