FP Flash Emulation for manual cameras?

Discussion in 'Lighting' started by T42, May 16, 2011.

  1. T42

    T42 Member

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    Hello Forum.

    Modern cameras and flash units support a feature called "High Speed Sync."

    As far as I can tell, this is a matter of an electronic flash unit pulsing for longer than the time of the sync shutter speed, so that light is available to the whole frame even if only a tiny open slit is running across the film/sensor.

    FP flash bulbs did this a generation or two ago.

    Here is my question:

    Does anyone here know of a flash which provides, or can be hacked to provide, flashed pulses for an amount of time which equals or exceeds the sync speed of a classic film camera like F2, M3 or whatever?

    Electronic FP flash emulation for manual focal plane shutter equipped cameras, in other words.

    Thanks.
     
  2. Diapositivo

    Diapositivo Subscriber

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    I was thinking about it in this thread (post #2).

    http://www.apug.org/forums/forum147/90466-adapting-leaf-shutter-lens-minolta-sony-35mm.html

    I would be grateful if anybody can give some contribution.

    I have no high-speed-synch flash but I suspect the following:

    An M, F or FP synchronization will fire - if I get it right - the flash bulb slightly before the opening of the shutter, to allow the bulb to reach its full luminosity.
    An X synchronization will fire the flash when the first curtain ends its trip.
    A "rear curtain" X synchronization will fire the flash a little before the second curtain begins its trip.
    A HSS synchronization will fire the flash before the first curtain begins its trip.

    I suspect that using an HSS flash with an X synchronization (be it on the first or the second curtain) will lead to a partial exposure of the film if a shutter speed faster than max X synchronization is employed. When the flash is fired, the second curtain is already on its way.

    An FP synchronization might work with an HSS flash because they both work by firing the flash before the first curtain opens.

    It might be necessary to cut communication (excluding hot contact) between camera and flash in case a dedicated flash sets the camera at max X synchro speed automatically as soon as it reaches full charge.

    If anybody has a HSS flash and would like to experiment with an old camera with an M or FP synchronization, that would be VERY useful for the community.

    Fabrizio
     
  3. T42

    T42 Member

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    Hello Fabrizio.

    Thanks for joining in.

    Yes, that is a fascinating point about X activating as soon as the first curtain is completely open. The light needs to begin pulsing before the instant that the opening curtain begins its travel across the film plane.

    So, there is a synchronizing issue here, as you say. Perhaps lighting the tube "prematurely" at one of the "warm up" sync settings like FP might work.

    I learned from fellow member Ian today that long ago the OM-4 SLR had a flash that could pulse for 40 milliseconds, accomplishing this. But I have not heard of it otherwise.

    Maybe we will learn something about how to do it here.

    :smile:
     
  4. Bill Burk

    Bill Burk Subscriber

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    Hi T42,

    Yes, Olympus made a pulsing flash that would be useful at all shutter speeds. I was locked out of taking advantage of it with my OM-4 as it was matched to the later OM-4T.

    You might go some steps better and get pulsed xenon lights from an old process camera. I bet those would make an impressive lighting kit.
     
  5. Diapositivo

    Diapositivo Subscriber

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    It's not just Olympus, it's pretty common these days:

    http://www.rpphoto.com/howto/view.asp?articleID=1026 (browse down for "a better solution" paragraph).

    The problem is that producers tend to have their flash to be "smart" and communicate with the camera so that, for instance, the high-sync feature is not available, on certain flashes, if the camera does not tell the flash that it supports it (I can understand the logic, but I would like to be able to override any logic). They also do that for marketing reasons probably, to tie the sale of their flash to the sale of their cameras.

    Nikon calls this Auto FP high-sync which tells a lot.

    I suppose that by interrupting communication between flash and camera (the dedicated pins) the feature could be available, with some flash, also with cameras that were designed before its advent.

    The fastest test would be to mount such a flash on an old camera that only has the hot sync (without additional electric contacts) and see what happens. Or use a flash cable. [EDIT: In any case the camera must have the FP, M or MP synchronization].

    I'm not going to buy a flash just to see if it works in fast-sync with my cameras, but I would certainly buy one if I knew that I can use fast-sync with my cameras. Check your flashes, if they are recent they may support fast-sync.

    Fabrizio
     
    Last edited by a moderator: May 17, 2011
  6. Diapositivo

    Diapositivo Subscriber

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    I have asked the question to the Italian distributor of Nikon products, Nital. I hope they actually read the question instead of giving me some pre-written stupid answer.

    I'll let you know the answer.

    This is the text of the question, for you daily exercise in Italian translation: :smile:

    Salve,
    ho e uso svariati apparecchi degli anni '80, alcuni dei quali, oltre alla sincronizzazione X, hanno la sincronizzazione per i flash a lampadina di una volta (indicata come M, MP, FP ecc).
    Con i flash a lampadina a combustione lenta era possibile usare qualsiasi tempo di otturazione, anche superiore al sincro X massimo ovviamente. Posso ad esempio usare la mia Minolta Srt-101 con un flash a lampadine usando la sincronizzazione FP e usando il tempo di otturazione di 1/1000.
    I flash a lampadine sono di rara reperibilità, le lampadine scottano... un flash elettronico è più rapido.
    Vorrei sapere se i vostri flash elettronici che hanno la funzione "FP fast sync" possono essere usati con fotocamere come la mia Minolta Srt-101, usando la sincronizzazione FP.
    Capisco perfettamente che il funzionamento sarà completamente manuale, e che il numero guida del flash sarà ridotto rispetto al funzionamento normale.
    Mi interessa solo sapere se il flash è in grado di comportarsi come un flash a lampade a combustione lenta senza bisogno di comunicazioni di alcun tipo con la macchina fotografica (salvo il contatto di sincronizzazione).
    Temo infatti che, se acquistassi un flash per usarlo con la mia Srt-101 in modalità FP, il flash si rifiuterebbe di impostarsi in quel modo in quanto non ha, dalla fotocamera, la conferma che quel modo viene supportato.
    Grazie della cortese risposta
     
  7. John Koehrer

    John Koehrer Subscriber

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    Metz offered several "strobing" flash units once upon a time. You could change the frequency of the tube but the initial triggering was from the shutter(X)
     
  8. jime11

    jime11 Member

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    backwards

    I've been thinking about this too.
    I have come to the conclusion that it can only be done backwards.
    That is, by having the flash actuate the shutter.
    By this I mean that you need a camera that can be fired remotely by the flash.
    This could overcome the latency issue without modifying the camera. As far as the electronics of pulsing a flash - I have no clue.
     
  9. ic-racer

    ic-racer Member

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    I felt this is only useful for the dinky little flashes on the cameras. Get a big powerful off-camera flash, it will allow you to stop down and make the background dark that way, without having to resort to this gimmick :wink:
     
  10. John Koehrer

    John Koehrer Subscriber

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    An alternative may be a strobe light used by a DJ or dance club.
    Turn the flash on and shoot, no sync necessary.
     
  11. Diapositivo

    Diapositivo Subscriber

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    I have just received the answer from Nital, Nikon distributor in Italy. They say that the FP function of their flash is only compatible with the Nikon bodies for which they are dedicated, and they "cannot be used" with a Srt-101.
     
  12. Steve Smith

    Steve Smith Subscriber

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    I think so too. If you use the camera to trigger the flash, it will start when the first curtain has finished its travel. By this time, with a shutter speed faster than its flash sync. speed, the second curtain will already have started its travel.


    Steve.
     
  13. Diapositivo

    Diapositivo Subscriber

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    If only the flash did not pretend to have to make love with the camera and just bloody worked when the camera tells it to work, everything would work because, as far as I know, using synchronization for bulb flashes (M, FP, whatever) always makes the camera fire the flash before the first curtain begins its travel, because bulbs need a small time to ignite so they have to be fired before the camera.

    It's a design "flaw" of those new "FP" flashes. They want to set themselves the camera to FP synchronization rather than X synchronization, and if the camera doesn't support FP synchronization (or doesn't have a way to tell it that it does, as is the case with old cameras) the flash will only work with the normal X synchronization method (one flash). It's also quite possible that those dedicated cameras cannot be set on FP synchronization on their own, only the flash can do it, so that one has to buy a flash of the same maker.

    If only there was a way to tell the flash "trust me a long emission is what I want, and I know better" any of those flashes would emulate a bulb flash and be compatible with any shutter speed on any camera with a bulb flash synchronization.
     
  14. T42

    T42 Member

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    Fascinating discussion, Guys. It seems to me that you are probably right, Diapositivo.

    Imagine having a flash which would begin pulsing when triggered by the shutter release, and which camera is using the camera's F sync connector or setting.

    Then the flash would pulse at ... say 20KHz for 1/30th of a second, or for an amount of time a little longer than the camera's so called sync speed, e.g. 1/125th (8ms), 1/60th(16.7ms), or 1/30th (33.3ms).

    Again, it would be triggered by the FP sync setting, such as is available on old classic 35s, like a Nikon F or Leica M, for example.

    The flash would begin firing even before the opening curtain leaves the gate, and the pulse stream would keep the flashtube illuminated until after the closing shutter finally covers the film.

    Does that sound right to you? Does to me. I wonder why no product can be configured to do this.

    :smile:
     
  15. AgX

    AgX Member

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    I think one "just" has to substitute the thyristor switching circuit of the flashlight by a new high-frequency switching circuit.

    But as with the commercially available ones the output (in the meaning of guide-number) would be low.
     
  16. baachitraka

    baachitraka Subscriber

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    Shooting with leaf shutter or cameras with high sync speed are easier than flash modding.