Pentax 645 - TTL AUTO FLASH OPERATION

TTL AUTO FLASH OPERATION
TTL auto flash unit
As illustrated, the light entering through the taking
lens strikes the film plane; a separate exclusive
photo sensor registers the light reflected off the film
plane and flash luminosity thereby is automaically
controlled. Since only the light reflected from the
subject is used for measuring purposes, an accurate
exposure is obtained. All available f/stops on the
lens may be also used for TTL auto flash control
although there are some limitations regarding the
flash-to-subject distance for each preset f/stop.
Completion of flash charging automatically adjusts
the shutter speed to the flash synchronization speed
of 1/60 sec. The marking will appear in both
windows to signify the completion of flash
charging.
Aperture set to respective f/stops [either in
Aperture-priority AE or Metered manual mode]
• Set the aperture ring to desired f/stop.
• Simultaneously with the completion of TTL auto
flash charging, the viewfinder LED will indicate
the flash synchronization speed of 1/60 sec.
Aperture set to ''A", [either in Programmed AE,
Aperture-priority AE or Shutter-priority AE]',
• Upon completion of the flash charging process of
the TTL auto flash, the viewfinder LED display
will indicate the flash synchronization speed of
1 /60 sec. and the aperture of f/4 with ISO 100
film (f/8 with the AF080C ring flash).
With a film of a different speed, the f/stop will
automatically change. However, the maximum
flash-to-subject distance will remain unchanged.
Refer to the operating manual of your flash
unit.
The standard 75mm f/2.8 lens is the only one
that can be used with the AF080C Ring Light.
(Use the 58 - ► 49mm Adapter Ring to fit the
flash on the lens.)
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