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Thread: Flash Question

  1. #1
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    Default Flash Question

    My friend have just bought a cheap automatic flash for his mechanical camera. May I know how does an automatic flash work? The one I have just comes with an on/off switch(super cheapo one), but on his I can see the table for the aperture/film speed, a sensor and 4 switch positions(off/max/blue region/red region). It is not a ttl flash. Sorry for this basic question coz I dunno anything abt flash...

  2. #2

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    To use an auto flash, you have to specify the aperture used and film ISO on the flash, match it to the settings you use in the camera. You can use any shutter speed as long as it is well within the flash sync speed. With the settings matched, the flash will then fire at the appropriate flash power. When the sensor deems that the flash exposure is sufficient, the flash output will be cut off.

    If your flash has only an on-off switch, my guess is that it's a full manual flash. It will fire at max power all the time, so you'll have to know the GN and do some maths to determine what aperture to use on the camera to get the correct exposure.

  3. #3
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    Default

    Originally posted by Tweek
    To use an auto flash, you have to specify the aperture used and film ISO on the flash, match it to the settings you use in the camera. You can use any shutter speed as long as it is well within the flash sync speed. With the settings matched, the flash will then fire at the appropriate flash power. When the sensor deems that the flash exposure is sufficient, the flash output will be cut off.

    Thanks for your reply... So lets say I use aperture 5.6 and shutter speed 1/125 sec, the flash will automatically decide the output of its flash, is it? What about the distance from the subject, won't that affect the flash too?

  4. #4

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    As long as your aperture and ISO match, the flash output should be correct. No need to worry about subject distance. This is only for auto flash hor, not manual flash.

  5. #5
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    Default

    Thanks Tweek!

  6. #6
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    Default

    Originally posted by Tweek
    It will fire at max power all the time, so you'll have to know the GN and do some maths to determine what aperture to use on the camera to get the correct exposure.
    Sorry, may I ask what is the GN?

  7. #7

    Talking

    Originally posted by Silverelf


    Sorry, may I ask what is the GN?
    guide number ..............

    plz correctme if me am wrong ...............


  8. #8
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    Default

    Oh!! I see!! paiseh... must go back and revise on flash liao...... sighz.... I'm hopeless at flash

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