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  1. #1

    Default Why doesn't the camera flash whine?

    We've been watching Silent Witness recently, one of the many excellent Pommy shows. In the show, they often take photographs of bodies, body parts and other evidence. The camera used has a flash and after the flash has fired I would expect to hear the whine of the capacitor recharging, but the only thing I can hear is the click of the shutter, so I wondered why it does not whine. Perhaps it does not use a capacitor. If not, what does it use for the flash? I would be interested to know.
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  2. #2
    Wrinkly Member! B.M.'s Avatar
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    Default Re: Why doesn't the camera flash whine?

    Quote Originally Posted by Roscoe View Post
    We've been watching Silent Witness recently, one of the many excellent Pommy shows. In the show, they often take photographs of bodies, body parts and other evidence. The camera used has a flash and after the flash has fired I would expect to hear the whine of the capacitor recharging, but the only thing I can hear is the click of the shutter, so I wondered why it does not whine. Perhaps it does not use a capacitor. If not, what does it use for the flash? I would be interested to know.
    You're showing your age Roscoe.
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  3. #3

    Default Re: Why doesn't the camera flash whine?

    Quote Originally Posted by B.M. View Post
    You're showing your age Roscoe.
    Alright then, call me a silly old fool if you must.
    It is better to wear out than to rust out.
    - Richard Chamberlain, Tour of the Hebrides

    Us husbands are a sorry lot.

  4. #4
    Senior Member 1101's Avatar
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    Default Re: Why doesn't the camera flash whine?

    Its a TV show. Not real life
    Sound effects are added/removed after its recorded .

    The whine was a chap in the back winding up the crank powered generator, to warm up the valves to power the powder flash charge they used .

  5. #5
    Senior Member piroska's Avatar
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    Default Re: Why doesn't the camera flash whine?

    what’s that high-pitched whine after I fire the flash?

    We learned that a flash requires more than a thousand volts, but batteries are only 1.5 to 9 volts. Your on-camera flash or speedlight has to boost the voltage from almost nothing to thousands of volts.

    Most modern speedlights use boost converters, sometimes called step-up converters, that take the power from a battery and increase the voltage. These are used in many applications, from electric vehicles, to portable lighting systems, to off-camera flash. They allow us to use much less powerful batteries or fewer batteries to accomplish a given task.

    Boost converters work by cycling a current back and forth, each time increasing the voltage. That annoying (or satisfying) whine you hear from your speedlight after you take a shot? That’s this voltage-boosting process powering up your flash so it’s ready for the next shot.

    Once the voltage is high enough, the current goes through a diode, which changes it into Direct Current (DC) and sends it to a capacitor, which stores the charge. This all happens fairly fast. If you have speedlights, you’ve likely heard the high-pitched whine and know about how long it takes to charge.

    A few new speedlights don’t have that whine and some photographers miss it. They used to know the speedlight was ready when the whine stopped. Now they have to adjust their work flow to look at the ready light on the flash. Sounds similar to those with mirrorless cameras who miss the click of a mechanical shutter and aren’t sure if they actually took a photo until they see it on their LCD screen. Some manufacturers have even added a mechanical shutter sound effect to compensate. Will flash manufacturers now have to add an artificial whine?

    So, there you have it. The “pop” of a flash is basically caused by the pressure shockwave generated when the gas in the flash tube gets jolted by a massive hit of voltage and instantaneously expands, heats up and generates light. The whine of many speedlights is caused when the boost converters are ramping up the voltage from your batteries for the next shot. All other noises, at least with this photographer, are from his aging joints doing a snap, crackle and pop and him whining about it.


    https://improvephotography.com/54300...sh-make-noise/
    Ex-pctek

  6. #6
    Computer "Specialist" Agent_24's Avatar
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    Default Re: Why doesn't the camera flash whine?

    It's the sound of the transformer (and possibly other components) in the flash capacitor charging circuit vibrating at an audible frequency.

    You can also hear a high frequency whine from the flyback transformer in a CRT monitor or TV.

  7. #7

    Default Re: Why doesn't the camera flash whine?

    Quote Originally Posted by Agent_24 View Post
    It's the sound of the transformer (and possibly other components) in the flash capacitor charging circuit vibrating at an audible frequency.
    Thank you for that Agent 24. I did not know what caused the whine. But that does not answer the original question.
    It is better to wear out than to rust out.
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    Us husbands are a sorry lot.

  8. #8
    Computer "Specialist" Agent_24's Avatar
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    Default Re: Why doesn't the camera flash whine?

    The frequency is probably too high and the audio level too low to be picked up easily on set, and adding it in post would probably make little sense as not everyone's equipment could reproduce it well or their ears hear it either.

  9. #9
    Retired old codger kenj's Avatar
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    Default Re: Why doesn't the camera flash whine?

    Perhaps, your hearing is like mine and don't hear the high pitched tones? Due to age I'm afraid Roscoe.

    Ken

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