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Thread: Rapax flash sync

  1. #1

    Rapax flash sync

    I have a pretty standard lens, but am unsure of the flash capabilities. It is a Wollensak Raptar 4.7/135mm mounted in a Rapax shutter. This is not the "synchromatic" model with selectable sync. Is this shutter compatible with electronic strobes? The intention is to use it with a Pentax AF 400T strobe. What speed range can this shutter work with strobes?

  2. #2

    Join Date
    Dec 2001
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    NJ
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    Rapax flash sync

    Select "X" and it will sync with electronic flash at all speeds.

  3. #3

    Rapax flash sync

    Dan, that is the issue. This model is not the "Synchromatic" that has a lever for M, B, and X selection. On those, the speeds that are within a range for a certain type of sync (M & X) are shown either in red or black. All speeds on this model are in black. This is why I need to know if it is compatible with X, or synched only for bulbs.

  4. #4

    Join Date
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    Rapax flash sync

    Try a simple test. Hook up the flash, and fire the shutter wlile looking through the lens. If you see the flash go off, you have X-sync. If the flash goes off and you can't see its light through the lens, it is synched for bulbs. The bulbs took several microseconds to fire, unlike electronic flash which is instantaneous. So at "M" sync the shutter fired the flash before the shutter opened, and with electronic flash it goes off ahead of time. No exposure! But a leaf shutter will work with flash at any speed, if it's synched right.

  5. #5

    Join Date
    Aug 2000
    Location
    California
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    3,049

    Rapax flash sync

    Rapax shutters - what great memories.

    Your shutter is synched for "M" type flash bulbs. It hasa a 5 millisecond delay, not a zero delay as used by electronic flash. It may synch at speeds slower than about 1/25, but not faster.
    Jim

  6. #6

    Rapax flash sync

    Actually the 5 millisecond synch was used for special "F" flash bulb that was filled with gas, rather then the usual foil "M" bulbs that synch at 20 milliseconds peak. My old Bush Pressman 2x3 had a graflex shutter that only synched with the the F bulb(not to be confused with the FP bulb). The only advantage I ever got with these gas filled bulbs was full light power at 1/200 second for action.

    Showing my age!

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