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Background: A Brief Guide Focusing and Exposure
Focusing, exposure and exposure metering are key factors in taking
photographs. By understanding these aspects of photography, you can
achieve a wider range of photographic effects.
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Focus and Depth of Field
When you focus the camera on a point, an area in front of and behind that
point is also in focus. This area is referred to as the depth of field and varies
depending on factors such as the distance to the subject, the focal length of
the lens and the aperture setting. In particular, narrowing the lens aperture
(selecting a higher f-stop) increases the distance over which objects are in
focus, giving what is referred to as a large depth of field. Conversely, widening
the lens aperture (selecting a lower f-stop) decreases the distance over which
objects are in focus, giving a shallow depth of field (
☞
P.67).
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Exposure
Exposure refers to the process by which light from the subject (the person or
object being photographed) passes through the camera lens, hits the film
(CCD) and is recorded. During this process, it is important that the sensitivity
of the CCD in the camera is matched to the brightness of the subject and that
the shutter speed and aperture are adjusted so that the correct amount of light
reaches the CCD (correct exposure).
To ensure optimum exposure, the FinePix S1 Pro is provided with a number of
exposure modes. These include the AUTO, programmed auto and image
program modes, in which the camera sets both the focus and the aperture
setting, the shutter-priority auto mode, in which the photographer sets the
shutter speed and the camera sets the exposure, the aperture-priority auto
mode, in which the photographer sets the exposure and the camera sets the
shutter speed, and manual mode, in which the photographer sets both the
shutter speed and the aperture setting by referring to the camera’s exposure
meter (
☞
P.64).
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Exposure Metering
The action of measuring the brightness of the subject (the person or object
being photographed) is referred to as exposure metering. Exposure metering
is an important source of information for determining the exposure. This
information is used to determine the combination of shutter speed and
aperture settings that will allow the optimum amount of light to hit the CCD.
Because the distribution of light in the image that includes the subject is not
necessarily uniform, the FinePix S1 Pro divides the image into 6 sections and
provides 2 types of exposure metering. These are “multi-pattern metering”, in
which the optimum exposure is determined using independently measured
light information for each section, and “center-weighted metering”, in which the
exposure metering information for the central part of the image is emphasized
in determining the optimum exposure.
If a D-type AF Nikkor lens is mounted on the camera, and additional metering
mode called “3D 6-zone multi-pattern metering” is available in which distance
information is also considered (
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P.69).
