Taking photos of strobe

Discussion in 'Digital Photography' started by BuzzyBee, Nov 26, 2007.

  1. BuzzyBee

    BuzzyBee Guest

    Hi,

    I'm wondering if anyone may be able to help me. I am wanting to
    photograph the airflow over a turbine blade being tested in a wind
    tunnel, via the attachment of small cotton threads to its surface.
    The only way to isolate the blade is to use a stroboscope and I would
    like to then take a photo of this, so I have a record of the direction
    the cotton threads are being blown in.

    I tried today without the strobe, and just using my flash gun. It
    wasn't too bad, but a little blurred still from the slow shutter
    speed. I've tried also using the bulb setting and letting the strobe
    pulse a few times hoping there would be enough light, but this wasn't
    very successful either.

    If anyway has ever photographed this sort of thing and has some clues
    on what I should do, I would be very grateful.

    Thanks in advance.
     
    BuzzyBee, Nov 26, 2007
    #1
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  2. BuzzyBee

    Cynicor Guest

    BuzzyBee wrote:
    > Hi,
    >
    > I'm wondering if anyone may be able to help me. I am wanting to
    > photograph the airflow over a turbine blade being tested in a wind
    > tunnel, via the attachment of small cotton threads to its surface.
    > The only way to isolate the blade is to use a stroboscope and I would
    > like to then take a photo of this, so I have a record of the direction
    > the cotton threads are being blown in.
    >
    > I tried today without the strobe, and just using my flash gun. It
    > wasn't too bad, but a little blurred still from the slow shutter
    > speed. I've tried also using the bulb setting and letting the strobe
    > pulse a few times hoping there would be enough light, but this wasn't
    > very successful either.
    >
    > If anyway has ever photographed this sort of thing and has some clues
    > on what I should do, I would be very grateful.


    Which camera, and which flash gun?
     
    Cynicor, Nov 26, 2007
    #2
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  3. On Mon, 26 Nov 2007 02:35:34 -0800 (PST), BuzzyBee <>
    wrote:

    >Hi,
    >
    >I'm wondering if anyone may be able to help me. I am wanting to
    >photograph the airflow over a turbine blade being tested in a wind
    >tunnel, via the attachment of small cotton threads to its surface.
    >The only way to isolate the blade is to use a stroboscope and I would
    >like to then take a photo of this, so I have a record of the direction
    >the cotton threads are being blown in.
    >
    >I tried today without the strobe, and just using my flash gun. It
    >wasn't too bad, but a little blurred still from the slow shutter
    >speed. I've tried also using the bulb setting and letting the strobe
    >pulse a few times hoping there would be enough light, but this wasn't
    >very successful either.
    >
    >If anyway has ever photographed this sort of thing and has some clues
    >on what I should do, I would be very grateful.
    >
    >Thanks in advance.


    You need to extinguish all ambient light and use the light of the flash alone.
    Also, if using automatic flash that might be depending on thyristor circuitry,
    it will help to be as close to the subject as possible. The closer you are, the
    less flash that is needed, and the shorter will be the duration of that flash.
    Flash output levels are controlled by its duration rather than luminosity (in
    most instances, because that is easier to control.)

    If you don't extinguish all ambient light and depend on flash alone, then the
    very slow speed of any dSLR's focal-plane shutter will also use the ambient
    light to expose those threads. Causing blurring, as you have seen. If you have
    access to a high-quality P&S camera instead, whose flash-sync isn't limited to
    last-century's focal-plane speeds, that will also help. One of my P&S cameras,
    for example, allows use of its flash up to its highest shutter speed of 1/2400
    (some others go higher than this), in perfect sync with full-frame illumination.
    If you use a P&S that can do this then you don't need to find ways to extinguish
    the ambient lights, which in some/many situations is impossible.
     
    barry--greene, Nov 26, 2007
    #3
  4. BuzzyBee

    Cynicor Guest

    barry--greene wrote:
    > On Mon, 26 Nov 2007 02:35:34 -0800 (PST), BuzzyBee <>
    > wrote:
    >
    >> Hi,
    >>
    >> I'm wondering if anyone may be able to help me. I am wanting to
    >> photograph the airflow over a turbine blade being tested in a wind
    >> tunnel, via the attachment of small cotton threads to its surface.
    >> The only way to isolate the blade is to use a stroboscope and I would
    >> like to then take a photo of this, so I have a record of the direction
    >> the cotton threads are being blown in.
    >>
    >> I tried today without the strobe, and just using my flash gun. It
    >> wasn't too bad, but a little blurred still from the slow shutter
    >> speed. I've tried also using the bulb setting and letting the strobe
    >> pulse a few times hoping there would be enough light, but this wasn't
    >> very successful either.
    >>
    >> If anyway has ever photographed this sort of thing and has some clues
    >> on what I should do, I would be very grateful.
    >>
    >> Thanks in advance.

    >
    > If you don't extinguish all ambient light and depend on flash alone, then the
    > very slow speed of any dSLR's focal-plane shutter will also use the ambient
    > light to expose those threads. Causing blurring, as you have seen. If you have
    > access to a high-quality P&S camera instead, whose flash-sync isn't limited to
    > last-century's focal-plane speeds, that will also help. One of my P&S cameras,
    > for example, allows use of its flash up to its highest shutter speed of 1/2400
    > (some others go higher than this), in perfect sync with full-frame illumination.
    > If you use a P&S that can do this then you don't need to find ways to extinguish
    > the ambient lights, which in some/many situations is impossible.


    Here's another piece of advice. Ignore trolls like this gentleman, and
    google the term "high-speed flash sync." Most DSLR/flash combinations
    will give you the ability to use flash at any shutter speed now, and the
    information in the paragraph above is simply false.
     
    Cynicor, Nov 26, 2007
    #4
  5. On Mon, 26 Nov 2007 09:04:20 -0500, Cynicor <>
    wrote:

    >barry--greene wrote:
    >> On Mon, 26 Nov 2007 02:35:34 -0800 (PST), BuzzyBee <>
    >> wrote:
    >>
    >>> Hi,
    >>>
    >>> I'm wondering if anyone may be able to help me. I am wanting to
    >>> photograph the airflow over a turbine blade being tested in a wind
    >>> tunnel, via the attachment of small cotton threads to its surface.
    >>> The only way to isolate the blade is to use a stroboscope and I would
    >>> like to then take a photo of this, so I have a record of the direction
    >>> the cotton threads are being blown in.
    >>>
    >>> I tried today without the strobe, and just using my flash gun. It
    >>> wasn't too bad, but a little blurred still from the slow shutter
    >>> speed. I've tried also using the bulb setting and letting the strobe
    >>> pulse a few times hoping there would be enough light, but this wasn't
    >>> very successful either.
    >>>
    >>> If anyway has ever photographed this sort of thing and has some clues
    >>> on what I should do, I would be very grateful.
    >>>
    >>> Thanks in advance.

    >>
    >> If you don't extinguish all ambient light and depend on flash alone, then the
    >> very slow speed of any dSLR's focal-plane shutter will also use the ambient
    >> light to expose those threads. Causing blurring, as you have seen. If you have
    >> access to a high-quality P&S camera instead, whose flash-sync isn't limited to
    >> last-century's focal-plane speeds, that will also help. One of my P&S cameras,
    >> for example, allows use of its flash up to its highest shutter speed of 1/2400
    >> (some others go higher than this), in perfect sync with full-frame illumination.
    >> If you use a P&S that can do this then you don't need to find ways to extinguish
    >> the ambient lights, which in some/many situations is impossible.

    >
    >Here's another piece of advice. Ignore trolls like this gentleman, and
    >google the term "high-speed flash sync." Most DSLR/flash combinations
    >will give you the ability to use flash at any shutter speed now, and the
    >information in the paragraph above is simply false.


    Please feel free to list all these "MOST DSLR/flash combinations" that allow
    this. It will save everyone the bother of trying to hunt down the one that does
    it. And does it poorly at that, by trying to emulate high-speed sync using cheap
    gimmicks.
     
    barry--greene, Nov 26, 2007
    #5
  6. BuzzyBee

    Pat Guest

    On Nov 26, 9:04 am, Cynicor <> wrote:
    > barry--greene wrote:
    > > On Mon, 26 Nov 2007 02:35:34 -0800 (PST), BuzzyBee <>
    > > wrote:

    >
    > >> Hi,

    >
    > >> I'm wondering if anyone may be able to help me. I am wanting to
    > >> photograph the airflow over a turbine blade being tested in a wind
    > >> tunnel, via the attachment of small cotton threads to its surface.
    > >> The only way to isolate the blade is to use a stroboscope and I would
    > >> like to then take a photo of this, so I have a record of the direction
    > >> the cotton threads are being blown in.

    >
    > >> I tried today without the strobe, and just using my flash gun. It
    > >> wasn't too bad, but a little blurred still from the slow shutter
    > >> speed. I've tried also using the bulb setting and letting the strobe
    > >> pulse a few times hoping there would be enough light, but this wasn't
    > >> very successful either.

    >
    > >> If anyway has ever photographed this sort of thing and has some clues
    > >> on what I should do, I would be very grateful.

    >
    > >> Thanks in advance.

    >
    > > If you don't extinguish all ambient light and depend on flash alone, then the
    > > very slow speed of any dSLR's focal-plane shutter will also use the ambient
    > > light to expose those threads. Causing blurring, as you have seen. If you have
    > > access to a high-quality P&S camera instead, whose flash-sync isn't limited to
    > > last-century's focal-plane speeds, that will also help. One of my P&S cameras,
    > > for example, allows use of its flash up to its highest shutter speed of 1/2400
    > > (some others go higher than this), in perfect sync with full-frame illumination.
    > > If you use a P&S that can do this then you don't need to find ways to extinguish
    > > the ambient lights, which in some/many situations is impossible.

    >
    > Here's another piece of advice. Ignore trolls like this gentleman, and
    > google the term "high-speed flash sync." Most DSLR/flash combinations
    > will give you the ability to use flash at any shutter speed now, and the
    > information in the paragraph above is simply false.- Hide quoted text -
    >
    > - Show quoted text -


    Cynicor is basically right, at least with Canon gear. Get a Canon
    EX550 or 580 and put it in high-speed sync mode. Then put your camera
    to 1/4000 or so and it'll sync. You'll need all outside light
    extinguished and you'll need to be pretty close, but it'll work.

    The second option is to get an external strobe (hey, if you're testing
    jet engines you'll have some resources). Get a strobe that is bright
    and quick. Put the camera in bulb mode and flash the strobe once.
    That'll work but you'll have to play with your aperature to get the
    right exposure.
     
    Pat, Nov 26, 2007
    #6
  7. BuzzyBee

    Roy G Guest

    "barry--greene" <> wrote in message
    news:...
    > On Mon, 26 Nov 2007 09:04:20 -0500, Cynicor
    > <>
    > wrote:
    >
    >>barry--greene wrote:
    >>> On Mon, 26 Nov 2007 02:35:34 -0800 (PST), BuzzyBee
    >>> <>
    >>> wrote:
    >>>
    >>>> Hi,
    >>>>
    >>>> I'm wondering if anyone may be able to help me. I am wanting to
    >>>> photograph the airflow over a turbine blade being tested in a wind
    >>>> tunnel, via the attachment of small cotton threads to its surface.
    >>>> The only way to isolate the blade is to use a stroboscope and I would
    >>>> like to then take a photo of this, so I have a record of the direction
    >>>> the cotton threads are being blown in.
    >>>>
    >>>> I tried today without the strobe, and just using my flash gun. It
    >>>> wasn't too bad, but a little blurred still from the slow shutter
    >>>> speed. I've tried also using the bulb setting and letting the strobe
    >>>> pulse a few times hoping there would be enough light, but this wasn't
    >>>> very successful either.
    >>>>
    >>>> If anyway has ever photographed this sort of thing and has some clues
    >>>> on what I should do, I would be very grateful.
    >>>>
    >>>> Thanks in advance.
    >>>
    >>> If you don't extinguish all ambient light and depend on flash alone,
    >>> then the
    >>> very slow speed of any dSLR's focal-plane shutter will also use the
    >>> ambient
    >>> light to expose those threads. Causing blurring, as you have seen. If
    >>> you have
    >>> access to a high-quality P&S camera instead, whose flash-sync isn't
    >>> limited to
    >>> last-century's focal-plane speeds, that will also help. One of my P&S
    >>> cameras,
    >>> for example, allows use of its flash up to its highest shutter speed of
    >>> 1/2400
    >>> (some others go higher than this), in perfect sync with full-frame
    >>> illumination.
    >>> If you use a P&S that can do this then you don't need to find ways to
    >>> extinguish
    >>> the ambient lights, which in some/many situations is impossible.

    >>
    >>Here's another piece of advice. Ignore trolls like this gentleman, and
    >>google the term "high-speed flash sync." Most DSLR/flash combinations
    >>will give you the ability to use flash at any shutter speed now, and the
    >>information in the paragraph above is simply false.

    >
    > Please feel free to list all these "MOST DSLR/flash combinations" that
    > allow
    > this. It will save everyone the bother of trying to hunt down the one that
    > does
    > it. And does it poorly at that, by trying to emulate high-speed sync using
    > cheap
    > gimmicks.
    >


    Anyone who knows anything about Flash Photography, knows that the Camera
    Shutter Speed, (any Camera), is irrelevant to correct exposure when Flash is
    the predominant light source.

    Except of course for those people who leave the Camera on any kind of "Auto"
    setting.

    The effective exposure time becomes the duration of the Flash Burn time, and
    one 64thousands of a second is quite common for a flash gun set to " low
    power ".

    Ambient light might cause problems, by allowing some image recording,
    (Blur), outside of the Flash Burn Time but only if it is fairly high
    compared to the Flash output.

    The kind of camera used, and its sync speed, is entirely irrelevant, but the
    more powerful the Flash Gun, the better.

    Roy G
     
    Roy G, Nov 26, 2007
    #7
  8. On Mon, 26 Nov 2007 14:37:30 GMT, "Roy G" <> wrote:

    >
    >"barry--greene" <> wrote in message
    >news:...
    >> On Mon, 26 Nov 2007 09:04:20 -0500, Cynicor
    >> <>
    >> wrote:
    >>
    >>>barry--greene wrote:
    >>>> On Mon, 26 Nov 2007 02:35:34 -0800 (PST), BuzzyBee
    >>>> <>
    >>>> wrote:
    >>>>
    >>>>> Hi,
    >>>>>
    >>>>> I'm wondering if anyone may be able to help me. I am wanting to
    >>>>> photograph the airflow over a turbine blade being tested in a wind
    >>>>> tunnel, via the attachment of small cotton threads to its surface.
    >>>>> The only way to isolate the blade is to use a stroboscope and I would
    >>>>> like to then take a photo of this, so I have a record of the direction
    >>>>> the cotton threads are being blown in.
    >>>>>
    >>>>> I tried today without the strobe, and just using my flash gun. It
    >>>>> wasn't too bad, but a little blurred still from the slow shutter
    >>>>> speed. I've tried also using the bulb setting and letting the strobe
    >>>>> pulse a few times hoping there would be enough light, but this wasn't
    >>>>> very successful either.
    >>>>>
    >>>>> If anyway has ever photographed this sort of thing and has some clues
    >>>>> on what I should do, I would be very grateful.
    >>>>>
    >>>>> Thanks in advance.
    >>>>
    >>>> If you don't extinguish all ambient light and depend on flash alone,
    >>>> then the
    >>>> very slow speed of any dSLR's focal-plane shutter will also use the
    >>>> ambient
    >>>> light to expose those threads. Causing blurring, as you have seen. If
    >>>> you have
    >>>> access to a high-quality P&S camera instead, whose flash-sync isn't
    >>>> limited to
    >>>> last-century's focal-plane speeds, that will also help. One of my P&S
    >>>> cameras,
    >>>> for example, allows use of its flash up to its highest shutter speed of
    >>>> 1/2400
    >>>> (some others go higher than this), in perfect sync with full-frame
    >>>> illumination.
    >>>> If you use a P&S that can do this then you don't need to find ways to
    >>>> extinguish
    >>>> the ambient lights, which in some/many situations is impossible.
    >>>
    >>>Here's another piece of advice. Ignore trolls like this gentleman, and
    >>>google the term "high-speed flash sync." Most DSLR/flash combinations
    >>>will give you the ability to use flash at any shutter speed now, and the
    >>>information in the paragraph above is simply false.

    >>
    >> Please feel free to list all these "MOST DSLR/flash combinations" that
    >> allow
    >> this. It will save everyone the bother of trying to hunt down the one that
    >> does
    >> it. And does it poorly at that, by trying to emulate high-speed sync using
    >> cheap
    >> gimmicks.
    >>

    >
    >Anyone who knows anything about Flash Photography, knows that the Camera
    >Shutter Speed, (any Camera), is irrelevant to correct exposure when Flash is
    >the predominant light source.
    >
    >Except of course for those people who leave the Camera on any kind of "Auto"
    >setting.
    >
    >The effective exposure time becomes the duration of the Flash Burn time, and
    >one 64thousands of a second is quite common for a flash gun set to " low
    >power ".
    >
    >Ambient light might cause problems, by allowing some image recording,
    >(Blur), outside of the Flash Burn Time but only if it is fairly high
    >compared to the Flash output.
    >
    >The kind of camera used, and its sync speed, is entirely irrelevant, but the
    >more powerful the Flash Gun, the better.
    >
    >Roy G
    >


    Thanks, for your extremely inexperienced opinion in these matters. You've made
    your experience level perfectly clear.
     
    barry--greene, Nov 26, 2007
    #8
  9. On Nov 26, 8:04 am, Cynicor <> wrote:
    > barry--greene wrote:
    > > On Mon, 26 Nov 2007 02:35:34 -0800 (PST), BuzzyBee <>
    > > wrote:

    >
    > >> Hi,

    >
    > >> I'm wondering if anyone may be able to help me. I am wanting to
    > >> photograph the airflow over a turbine blade being tested in a wind
    > >> tunnel, via the attachment of small cotton threads to its surface.
    > >> The only way to isolate the blade is to use a stroboscope and I would
    > >> like to then take a photo of this, so I have a record of the direction
    > >> the cotton threads are being blown in.

    >
    > >> I tried today without the strobe, and just using my flash gun. It
    > >> wasn't too bad, but a little blurred still from the slow shutter
    > >> speed. I've tried also using the bulb setting and letting the strobe
    > >> pulse a few times hoping there would be enough light, but this wasn't
    > >> very successful either.

    >
    > >> If anyway has ever photographed this sort of thing and has some clues
    > >> on what I should do, I would be very grateful.

    >
    > >> Thanks in advance.

    >
    > > If you don't extinguish all ambient light and depend on flash alone, then the
    > > very slow speed of any dSLR's focal-plane shutter will also use the ambient
    > > light to expose those threads. Causing blurring, as you have seen. If you have
    > > access to a high-quality P&S camera instead, whose flash-sync isn't limited to
    > > last-century's focal-plane speeds, that will also help. One of my P&S cameras,
    > > for example, allows use of its flash up to its highest shutter speed of 1/2400
    > > (some others go higher than this), in perfect sync with full-frame illumination.
    > > If you use a P&S that can do this then you don't need to find ways to extinguish
    > > the ambient lights, which in some/many situations is impossible.

    >
    > Here's another piece of advice. Ignore trolls like this gentleman, and
    > google the term "high-speed flash sync." Most DSLR/flash combinations
    > will give you the ability to use flash at any shutter speed now, and the
    > information in the paragraph above is simply false.


    If the admonition to exclude ambient light is followed, the flash time
    is what counts- the shutter speed is unimportant. Only while the
    flash lasts is there light for the exposure, and the flash is much
    shorter than the shutter speed.
     
    Don Stauffer in Minnesota, Nov 26, 2007
    #9
  10. BuzzyBee

    Chris Savage Guest

    On 2007-11-26, Roy G <> wrote:
    >
    > Ambient light might cause problems, by allowing some image recording,
    > (Blur), outside of the Flash Burn Time but only if it is fairly high
    > compared to the Flash output.
    >
    > The kind of camera used, and its sync speed, is entirely irrelevant, but the
    > more powerful the Flash Gun, the better.
    >


    I couldn't resist peeking at the nymshifter's reply to this. He really
    is losing it, I can see the facial tics from all the way over here.

    --
    Chris Savage Kiss me. Or would you rather live in a
    Gateshead, UK land where the soap won't lather?
    - Billy Bragg
     
    Chris Savage, Nov 26, 2007
    #10
  11. barry--greene <> writes:

    >You need to extinguish all ambient light and use the light of the flash alone.
    >Also, if using automatic flash that might be depending on thyristor circuitry,
    >it will help to be as close to the subject as possible. The closer you are, the
    >less flash that is needed, and the shorter will be the duration of that flash.
    >Flash output levels are controlled by its duration rather than luminosity (in
    >most instances, because that is easier to control.)


    Some flashes have a manual mode that lets you set the light output.
    This is generally done by reducing duration, so selecting 1/16 power
    will get you a much shorter flash pulse than full power.

    The other option is to use flashes that are designed for particularly
    short pulses, from the scientific world instead of consumer
    photography.

    Dave
     
    Dave Martindale, Nov 26, 2007
    #11
  12. Cynicor <> writes:

    >Here's another piece of advice. Ignore trolls like this gentleman, and
    >google the term "high-speed flash sync." Most DSLR/flash combinations
    >will give you the ability to use flash at any shutter speed now, and the
    >information in the paragraph above is simply false.


    But find out how the "high speed flash sync" actually works before
    buying the camera/flash combination.

    If it keeps the focal plane shutter slit small, but simply fires the
    flash multiple times during the curtain travel, you actually get many
    short exposures, and the image of your streaming trailers will actually
    be a composite from many different times.

    If the camera does high-speed flash sync by actually using a slow
    mechanical shutter (so the sensor is fully uncovered) plus a fast
    electronic shutter (to ignore light that leaks through when the
    mechanical shutter is open) and a single pulse of light from the flash,
    then you should be OK.

    Dave
     
    Dave Martindale, Nov 26, 2007
    #12
  13. BuzzyBee

    Roy G Guest

    "barry--greene" <> wrote in message
    news:...
    > On Mon, 26 Nov 2007 14:37:30 GMT, "Roy G" <> wrote:
    >
    >>
    >>"barry--greene" <> wrote in message
    >>news:...
    >>> On Mon, 26 Nov 2007 09:04:20 -0500, Cynicor
    >>> <>
    >>> wrote:
    >>>
    >>>>barry--greene wrote:
    >>>>> On Mon, 26 Nov 2007 02:35:34 -0800 (PST), BuzzyBee
    >>>>> <>
    >>>>> wrote:
    >>>>>
    >>>>>> Hi,
    >>>>>>
    >>>>>> I'm wondering if anyone may be able to help me. I am wanting to
    >>>>>> photograph the airflow over a turbine blade being tested in a wind
    >>>>>> tunnel, via the attachment of small cotton threads to its surface.
    >>>>>> The only way to isolate the blade is to use a stroboscope and I would
    >>>>>> like to then take a photo of this, so I have a record of the
    >>>>>> direction
    >>>>>> the cotton threads are being blown in.
    >>>>>>
    >>>>>> I tried today without the strobe, and just using my flash gun. It
    >>>>>> wasn't too bad, but a little blurred still from the slow shutter
    >>>>>> speed. I've tried also using the bulb setting and letting the strobe
    >>>>>> pulse a few times hoping there would be enough light, but this wasn't
    >>>>>> very successful either.
    >>>>>>
    >>>>>> If anyway has ever photographed this sort of thing and has some clues
    >>>>>> on what I should do, I would be very grateful.
    >>>>>>
    >>>>>> Thanks in advance.
    >>>>>
    >>>>> If you don't extinguish all ambient light and depend on flash alone,
    >>>>> then the
    >>>>> very slow speed of any dSLR's focal-plane shutter will also use the
    >>>>> ambient
    >>>>> light to expose those threads. Causing blurring, as you have seen. If
    >>>>> you have
    >>>>> access to a high-quality P&S camera instead, whose flash-sync isn't
    >>>>> limited to
    >>>>> last-century's focal-plane speeds, that will also help. One of my P&S
    >>>>> cameras,
    >>>>> for example, allows use of its flash up to its highest shutter speed
    >>>>> of
    >>>>> 1/2400
    >>>>> (some others go higher than this), in perfect sync with full-frame
    >>>>> illumination.
    >>>>> If you use a P&S that can do this then you don't need to find ways to
    >>>>> extinguish
    >>>>> the ambient lights, which in some/many situations is impossible.
    >>>>
    >>>>Here's another piece of advice. Ignore trolls like this gentleman, and
    >>>>google the term "high-speed flash sync." Most DSLR/flash combinations
    >>>>will give you the ability to use flash at any shutter speed now, and the
    >>>>information in the paragraph above is simply false.
    >>>
    >>> Please feel free to list all these "MOST DSLR/flash combinations" that
    >>> allow
    >>> this. It will save everyone the bother of trying to hunt down the one
    >>> that
    >>> does
    >>> it. And does it poorly at that, by trying to emulate high-speed sync
    >>> using
    >>> cheap
    >>> gimmicks.
    >>>

    >>
    >>Anyone who knows anything about Flash Photography, knows that the Camera
    >>Shutter Speed, (any Camera), is irrelevant to correct exposure when Flash
    >>is
    >>the predominant light source.
    >>
    >>Except of course for those people who leave the Camera on any kind of
    >>"Auto"
    >>setting.
    >>
    >>The effective exposure time becomes the duration of the Flash Burn time,
    >>and
    >>one 64thousands of a second is quite common for a flash gun set to " low
    >>power ".
    >>
    >>Ambient light might cause problems, by allowing some image recording,
    >>(Blur), outside of the Flash Burn Time but only if it is fairly high
    >>compared to the Flash output.
    >>
    >>The kind of camera used, and its sync speed, is entirely irrelevant, but
    >>the
    >>more powerful the Flash Gun, the better.
    >>
    >>Roy G
    >>

    >
    > Thanks, for your extremely inexperienced opinion in these matters. You've
    > made
    > your experience level perfectly clear.
    >

    OK Moron-

    Now is your chance to explain to everyone exactly what is incorrect about my
    explanation.

    Go on tell us just what you do know about Flash Photography.

    Roy G
     
    Roy G, Nov 26, 2007
    #13
  14. BuzzyBee

    BuzzyBee Guest

    On Nov 26, 10:53 pm, Cynicor <> wrote:
    > BuzzyBee wrote:
    > > Hi,

    >
    > > I'm wondering if anyone may be able to help me. I am wanting to
    > > photograph the airflow over a turbine blade being tested in a wind
    > > tunnel, via the attachment of small cotton threads to its surface.
    > > The only way to isolate the blade is to use a stroboscope and I would
    > > like to then take a photo of this, so I have a record of the direction
    > > the cotton threads are being blown in.

    >
    > > I tried today without the strobe, and just using my flash gun. It
    > > wasn't too bad, but a little blurred still from the slow shutter
    > > speed. I've tried also using the bulb setting and letting the strobe
    > > pulse a few times hoping there would be enough light, but this wasn't
    > > very successful either.

    >
    > > If anyway has ever photographed this sort of thing and has some clues
    > > on what I should do, I would be very grateful.

    >
    > Which camera, and which flash gun?


    Hi,

    I'm using a Nikon D70 with an SB600 flash gun.
     
    BuzzyBee, Nov 27, 2007
    #14
  15. BuzzyBee

    Ray Fischer Guest

    barry--greene <> wrote:
    > "Roy G" <> wrote:


    >>Anyone who knows anything about Flash Photography, knows that the Camera
    >>Shutter Speed, (any Camera), is irrelevant to correct exposure when Flash is
    >>the predominant light source.
    >>
    >>Except of course for those people who leave the Camera on any kind of "Auto"
    >>setting.
    >>
    >>The effective exposure time becomes the duration of the Flash Burn time, and
    >>one 64thousands of a second is quite common for a flash gun set to " low
    >>power ".
    >>
    >>Ambient light might cause problems, by allowing some image recording,
    >>(Blur), outside of the Flash Burn Time but only if it is fairly high
    >>compared to the Flash output.
    >>
    >>The kind of camera used, and its sync speed, is entirely irrelevant, but the
    >>more powerful the Flash Gun, the better.

    >
    >Thanks, for your extremely inexperienced opinion in these matters. You've made
    >your experience level perfectly clear.


    As a "rebuttal" that was childish, asinine, and dishonest.

    Run along, asshole - you've been spanked.

    --
    Ray Fischer
     
    Ray Fischer, Nov 27, 2007
    #15
  16. BuzzyBee

    Nick Fotis Guest

    BuzzyBee wrote:

    > I'm using a Nikon D70 with an SB600 flash gun.


    If I remember correctly, the D70 can sync up to 1/500" speeds.

    Put your camera into Manual mode (M), push the speed to 1/500" and open the
    aperture as much as needed. Keep your ISO sensitivity as low as possible.

    In order to make the flash the exclusive light source, you must record as
    less of the ambient lights are possible (here, the high shutter speed of
    the camera means that the ambient light is less recorded into the final
    image). You may want to use an grey ND 'neutral density' filter, in order
    to lower even more the ambient light.

    If you cannot close all ambient light sources, you will have to raise the
    shutter speed and put your flash in High-Speed flash mode (this usually
    means lower range, though).

    Put your SB600 into Manual mode and select, say, 1/4 of power with an
    aperture of 5.6 (don't know how large is your engine, but let's start with
    these numbers, raise the power progressively up to 1/1 if the reach isn't
    enough).

    Hope this will give you 'good enough' photos. Please tell us back if the
    results were good (upload some samples to Imageshack or another site, if
    you wish, for some more ideas).

    Cheers,
    N.F.
     
    Nick Fotis, Nov 27, 2007
    #16
  17. BuzzyBee

    nospam Guest

    In article <figrpk$1qga$>, Nick Fotis
    <> wrote:

    > BuzzyBee wrote:
    >
    > > I'm using a Nikon D70 with an SB600 flash gun.

    >
    > If I remember correctly, the D70 can sync up to 1/500" speeds.


    it can sync at any speed with non-nikon flashes. nikon flashes
    (including the sb-600) will limit it to 1/500, but that is trivially
    overidden.
     
    nospam, Nov 27, 2007
    #17
  18. BuzzyBee

    Chuck Guest

    First, can you adjust the strobe light flash rate to sync with the turbine
    blades?
    If so, use only the strobe light. Use an F stop that allows you to focus on
    only the area of interest.
    I have no idea of the light level produced by the strobe, so I cannot say
    what you should set for in terms of shutter speed.
    and ISO. Manual focus, F stop, and shutter speed is required. We used to
    do this quite regularly about 35 years ago using film and high speed cameras
    that used spinning slit shutters, as well as conventional 35mm SLR cameras
    with a "prefog" light.
    (Pictures of moving parts in electrical devices such as relays.) A small
    amount of ambient light may actually help.

    "Dave Martindale" <> wrote in message
    news:fifbm0$k4m$...
    > barry--greene <> writes:
    >
    > >You need to extinguish all ambient light and use the light of the flash

    alone.
    > >Also, if using automatic flash that might be depending on thyristor

    circuitry,
    > >it will help to be as close to the subject as possible. The closer you

    are, the
    > >less flash that is needed, and the shorter will be the duration of that

    flash.
    > >Flash output levels are controlled by its duration rather than luminosity

    (in
    > >most instances, because that is easier to control.)

    >
    > Some flashes have a manual mode that lets you set the light output.
    > This is generally done by reducing duration, so selecting 1/16 power
    > will get you a much shorter flash pulse than full power.
    >
    > The other option is to use flashes that are designed for particularly
    > short pulses, from the scientific world instead of consumer
    > photography.
    >
    > Dave
     
    Chuck, Nov 30, 2007
    #18
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