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Focus Tracking
Enables the camera to analyze the speed of the moving subject
according to the focus data detected, and to obtain correct
focus by anticipating the subject’s position—and driving the
lens to that position—at the exact moment of exposure.
f-number
The numbers on the lens aperture ring and on the camera’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.
Focal length
The distance from the principal point to the focal point. In
35mm-format cameras, lenses with a focal length of approx.
50mm are called normal or standard lenses. Lenses with a
focal length less than approx. 35mm are called wideangle
lenses, and lenses with a focal length more than approx. 85mm
are called telephoto lenses. Lenses which allow the user to
continuously vary the focal length without changing focus are
called zoom lenses.
Front-Curtain Sync
The flash fires an instant after the front curtain of a focal plane
shutter has completed its travel across the film plane. This is
the way the F70/F70
D
operates with the flash sync mode at
Normal Sync. (See "Rear-Curtain Sync".)
Guide number
The guide number indicates the power of a flash in relation to
ISO film speed. Guide numbers are quoted in either meters or
feet. Guide numbers are used to calculate the f/stop for correct
exposure as follows:
guide number
f/stop = ———————————
flash-to-subject distance
Using a selected aperture, we can calculate the required flash-
to-subject distance with the formula:
guide number
flash-to-subject distance = ———————
f/stop
Useful for determining the maximum flash-to-subject distance
for flash photography.
Exposure control
Programmed Auto: Camera sets both shutter speed and
aperture for correct exposure. F70/F70D camera applies two
Programmed Auto Exposure Control, Auto-Multi Program and
Vari-Program.
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.
Flash Exposure Bracketing
Enables a photographer to automatically bracket exposures at
varied flash output levels, in TTL auto flash shooting, without
changing the shutter speed and/or aperture. (See "Exposure
bracketing".)
Flash Output Level Compensation
A control used to adjust a TTL auto flash operation, enabling an
increase or decrease of flash output to lighten or darken the
flash effect.
Flash shooting distance range
The distance range over which a flash can effectively provide
light. Flash shooting distance range is controlled by the amount
of flash output available. Each automatic Speedlight’s flash
output varies from maximum duration to minimum duration.
Close-up subjects will require lower (to minimum) output, while
more distant subjects will require more light up to the maximum
output.
The flash shooting distance range varies with the aperture, film
speed, etc.
Flash sync speed
Shutter speed at which the entire film frame to be open when
the flash is fired in flash shooting. The F70/F70D’s flash sync
speed is 1/125 sec. or slower.
Flexible Program
Flexible Program function temporarily shifts an automatically
selected shutter speed/aperture combination while maintaining
correct exposure. That is, a desired shutter speed or aperture
can be selected in Programmed Auto exposure mode.
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