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  1. #1
    fehn is offline I'm new here!
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    Default Slow Snyc Flash with 40d problems

    With the built in flash it is possible to do 1st curtain slow syncs but when the flash is set to 2nd curtain it discharges at the begin in and the end of the exposure. Is there any way to only have it flash at the end of the exposure?
    thanks, Fehn

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    PhotoNewt's Avatar
    PhotoNewt is offline dPS Forum Member
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    Quote Originally Posted by fehn View Post
    With the built in flash it is possible to do 1st curtain slow syncs but when the flash is set to 2nd curtain it discharges at the begin in and the end of the exposure. Is there any way to only have it flash at the end of the exposure?
    thanks, Fehn
    Short answer; NO.

    Long answer; the first is a "pre-flash" for the E-TTL (Evaluative Thru-The-Lens) metering system needed to calculate the required flash output to appropriately expose the subject. The second is the "real" flash that actually exposes the scene and is fired just before the shutter curtain closes.

    You also have the same two flashes when you use 1st curtain or 2nd curtain with a fast shutter speed (i.e., 1/250), however they fire so close together that you see them as a single flash.
    ~ Newt ~
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