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Exposure control
Programmed auto: Camera sets both shutter speed and
aperture for correct exposure.
Shutter-Priority auto:
User
selects shutter speed and camera
sets matching lens aperture
for
correct exposure.
Aperture-Priority auto:
User
selects aperture and camera sets
matching shutter speed for correct
exposure.
Manual: User
selects
both
shutter speed and aperture,
following or ignoring the meter's
recommendations
(by
LCD
readout)
to
achieve the desired exposure.
Fill-flash
A
method of
flash
photography which combines flash
illumination
and ambient
light,
but
does not necessarily
attempt
to balance these two types of
illumination.
Focus-Priority for autofocus
Shutter cannot be released
until
subject
is
in
focus. Suitable
when in-focus subject
is important.
With N90
camera body,
Focus-Priority is
given
to
Single Servo
AF
mode while
Release-Priority
is given to Continuous Servo
AF. However,
the
Electronic
Organizer can change priority to
perform
Release-Priority
Single Servo
AF
or
Focus-Priority
Continuous Servo
AF.
140
Flash synchronization
The
timing of the
flash
so
it fires
coincident with the operation of
the
camera's shutter.
There
are two types of synchronization:
Normal
Sync which fires the flash at
the
start of the exposure,
and Rear
Sync which fires
the flash
at the end of the exposure.
f-number
The
numbers on
the lens
aperture ring and on the
N90's
LCD
which indicate
the
relative
size of
the lens
aperture opening
.
The f-number
series is a geometric progression based on
changes in
the
size of the
lens
aperture, as it is opened and
closed.
As
the scale rises, each number is multiplied by the
factor
1.4.
The standard numbers for calibration are
1.0,
1.4,
2,
2.8,4,5.6,8, 11,16,22,32, etc., and each
change
results
in a
doubling
or halving of the amount of light
transmitted
by the
lens.
Hyperfocal distance
The closest
point
a photographer can focus on where
the
depth of
field
includes
infinity.
When
the
lens is focused
for
hyperfocal
distance,
the
deepest
depth
of
field,
covering from
1/2
the hyperfocal
distance
to infinity,
can be obtained at each
f/stop. The longer
the focal length,
the longer
the
hyperfocal
distance;
the smaller the aperture (the
larger
the f/number), the
shorter
the
hyperfocal distance.
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