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Thread: Has anyone tried this - sync beyond max sync speed

  1. #41
    Moderator Manfred M's Avatar
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    Re: Has anyone tried this - sync beyond max sync speed

    Quote Originally Posted by george013 View Post
    The exif still states "compulsery flash". I can't find a good explanation for that phrase but to me it's FP flash.
    If so, you're looking for the limits of FP, not of manual. Lower the shutterspeed and find out where that "compulsery flash" comes up.

    George
    George - in those shots the flash used was not capable of FP/HSS, or in fact even communicating with the camera. The camera was set so FP/HSS was enabled (at 1/250, as per the instructions by PocketWizard for Hyper-Synch), as that is the only way that speeds higher than synch speed can be selected on the camera. The PocketWizard FlexTT5 was set so that FP / HSS was DISABLED.

    My guess is that this is reported by the camera when it detects a flash is used and the shutter speed selected is higher than the synch speed of the camera.

  2. #42

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    Re: Has anyone tried this - sync beyond max sync speed

    Quote Originally Posted by GrumpyDiver View Post
    George - in those shots the flash used was not capable of FP/HSS, or in fact even communicating with the camera. The camera was set so FP/HSS was enabled (at 1/250, as per the instructions by PocketWizard for Hyper-Synch), as that is the only way that speeds higher than synch speed can be selected on the camera. The PocketWizard FlexTT5 was set so that FP / HSS was DISABLED.

    My guess is that this is reported by the camera when it detects a flash is used and the shutter speed selected is higher than the synch speed of the camera.
    Manfred,
    Let's put some understandings on a rail.
    1. The camera has a curtain shutter. First curtain opens, second closes after a while..
    2. The sync speed is the minimal shutterspeed that has a fully exposed sensor.
    3. A faster shutterspeed is created by closing the second curtain before the first curtain is fully opened.
    4. The consequence of a faster shutterspeed as the sync speed is that a band of light is travelling across the sensor.
    5. The faster the shutterspeed, the smaller that band of light.
    6. With normal flash and a short flash duration you will see a shadow of the second curtain if using a shutterspeed faster as the sync speed.

    Now lets assume that with full power, the flash duration is about the sync speed. In that case you can see that flash as a continuous light. With faster speed the amount of light reaching the sensor is limited by the band of light travelling the sensor. Looking at your photo's, they are made with 1/1250 and 1/8000, others settings the same. A difference of 6.4 stops. I don't see that back in your photo's.

    With the knowledge I have at this moment, that's only possible with FP flash. I've a feeling that HSS is used in different meanings.

    I also understood from http://speedlights.net/2010/12/21/ni...dlight-review/ that there are several ways to cummunicate with the slave, optical like that guy in the video with his lighter, something like SU-4 and TTL. I understood that in TTL the master is controlling the slave.

    That Nikon cls-sytem is a quite complex system.

    George

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