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Thread: Knowledge appreciated

  1. #1

    Default Knowledge appreciated

    Would appreciate any links cos like to know about the functions and 'know-how' on the following topis.....Front-Curtain Sync (normal sync)
    Red-Eye Reduction
    Red-Eye Reduction with Slow Sync
    Slow Sync
    Rear-Curtain Sync

  2. #2
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    Default Re: Knowledge appreciated

    Originally posted by Jethro
    Would appreciate any links cos like to know about the functions and 'know-how' on the following topis.....Front-Curtain Sync (normal sync)
    ?Red-Eye Reduction
    ?Red-Eye Reduction with Slow Sync
    ?Slow Sync
    ?Rear-Curtain Sync
    Front curtain (normal) sync :
    1. Shutter opens.
    2. Flash fires.
    3. Shutter closes after a duration of the flash sync shutter speed (e.g. 1/250)

    Slow Sync
    1. Camera uses a shutter speed typically lower than 1/60.
    2. shutter opens
    3. flash fires immediately
    4. shutter closes after a length of time based on the set shutter.

    Red Eye reduction
    1. red-eye reduction lamp fires
    2. shutter opens
    3. Flash fires immediately
    4. Shutter closes

    Red Eye Reduction with slow sync
    1. red-eye reduction lamp fires
    2. Camera uses a shutter speed typically lower than 1/60.
    3. shutter opens
    4. flash fires.
    5. shutter closes after a length of time based on the set shutter.

    Rear curtain sync
    1. shutter opens
    2. flash fires just before shutter closes
    3. shutter closes.

    Those with red eye are not very useful as they introduce a significant delay.

    Slow sync is useful if you want a longer shutter speed to capture ambient lighting. e.g. if you want to take a pic of your friend with the singapore skyline in the background (obviously tripod needed).

    Rear-curtain will fire the flash just before shutter closes, freezing the subject at end of exposure.

    Front curtain will fire first, freezing the subject. But if shutter speed is long, subject will leave a blur/ghost.

    Regards
    CK

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    Default

    how does red-eye reduction work theortically???

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    ClubSNAP Admin Darren's Avatar
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    Default

    Originally posted by kamwai
    how does red-eye reduction work theortically???
    Theoretically, in a dim situation, the pupil of the eye opens up to let in more light. Redeye occurs when a direct beam of light enters the enlarged pupil and bounces off the retina.

    To prevent redeye, a low power preflash is made 0.5-1sec before the main flash - the pupil reacts quickly to the preflash and thus "stops down 2-3 stops".

    Since there is less pupil opening, theoretically there will be less redeye.

    The amount of redeye reduction will depend on several factors:-
    1. distance of flash from lens
    2. brightness or lack thereof
    3. lazy eyes which refure to stop down

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    A tip from a photographer I know who shoots events and such. When photographing a speaker giving a speech, good way to prevent red eye is to let the other photographers shoot him first. Their flash will act as a red-eye reduction lamp or pre-flash. And you can shoot away without the delay associated with turning on the red-eye reduction.

    Regards
    CK

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    Default

    Originally posted by Darren


    Theoretically, in a dim situation, the pupil of the eye opens up to let in more light. Redeye occurs when a direct beam of light enters the enlarged pupil and bounces off the retina.

    To prevent redeye, a low power preflash is made 0.5-1sec before the main flash - the pupil reacts quickly to the preflash and thus "stops down 2-3 stops".

    Since there is less pupil opening, theoretically there will be less redeye.

    The amount of redeye reduction will depend on several factors:-
    1. distance of flash from lens
    2. brightness or lack thereof
    3. lazy eyes which refure to stop down
    VERY WELL ILLUSTRATED........

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    Does red-eye reduction reduce the power of the flash??

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    Originally posted by kamwai
    Does red-eye reduction reduce the power of the flash??
    Nope. It should not.

    Regards
    CK

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