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Thread: Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

  1. #21

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    Re: Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

    Quote Originally Posted by Bernice Loui View Post
    Yes indeediee Bob, watt/seconds is a relative measure. Same game with Guide Numbers.

    This is why using an accurate flash meter is absolutely essential. Once light modifiers are applied (which is nearly 100% of the time for proper strobe/flash heads) all this watt/seconds, Guide numbers babble become extremely meaningless.

    Fact is, two Elinchrom 404 (4000 watt/second) power packs into a X8000 flash head (8000 watt/seconds total) will produce a LOT more light output than any battery powered compact flash unit.. or why watt/second become a relative power output metric.


    Bernice
    No, that output will depend on the angle of coverage on that flash head.

  2. #22

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    Re: Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

    Quote Originally Posted by Bob Salomon View Post
    Bernice, isn’t it about time that you learned that watt seconds is not output, can not be converted directly to a guide number or actual output?
    Watt seconds is another major “marketing ploy”!
    watt-seconds isn't any more of a marketing ploy than the wattage listed on an incandescent bulb. it's just a measure of power input to give you a rough idea of the flash's output. guide numbers are way more questionable.

  3. #23
    Tin Can's Avatar
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    Re: Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

    I use a Sekonic L758 meter constantly

    I buy what I can afford as hobbyist

    Bob is a salesman

    I was also selling very expensive tools and I advised all beginners to buy what they could afford

    Then when they became better paid I gladly sold Pro stuff
    Tin Can

  4. #24

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    Re: Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

    Quote Originally Posted by maltfalc View Post
    watt-seconds isn't any more of a marketing ploy than the wattage listed on an incandescent bulb. it's just a measure of power input to give you a rough idea of the flash's output. guide numbers are way more questionable.
    Do some study watt seconds are the storage capacity of the capacitors in a flash. An extremely efficient flash will not output more then 80% of that storage capacity. The actual output will depend on the diameter of the wires between the capacitors and the flash tube, the number of connectors between them, the design of the tube, the coverage of the reflector, etc.
    Assume that you have a 200ws flash. You take one shot without a reflector and another with a 50° coverage reflector. Both are 200ws. But their outputs are not nearly the same.
    Without knowing the loading capacity of the capacitors + the coverage of the reflector it is impossible to determine the gn. GN divided by the distance results in the exposure.
    Learn BCPS of your system and you can determine output. Learning the WS is like guessing output.

  5. #25
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    Re: Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

    I studied lighting patterns and various camera positions with the body and lighting set up to make flattering photographs of people. Those are two important ingredients when making photographs of people. There are others, like the environment, props, skin color, make up and clothing. I would work at a situation and I would determine, do I want the photograph to look like this?

    How I achieved proper exposure was by reviewing the first of a series of photographs using the historgram on the camera as a guide.

    When I was film based, I would use a polaroid back to check things out, then the film back was put on. Photography was much more limited back then.

    Here is an interesting and educational site on lighting and other ingredients:

    https://strobist.blogspot.com/
    Last edited by wclark5179; 14-May-2022 at 11:05.

  6. #26

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    Re: Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

    Quote Originally Posted by Bob Salomon View Post
    Do some study watt seconds are the storage capacity of the capacitors in a flash. An extremely efficient flash will not output more then 80% of that storage capacity. The actual output will depend on the diameter of the wires between the capacitors and the flash tube, the number of connectors between them, the design of the tube, the coverage of the reflector, etc.
    Assume that you have a 200ws flash. You take one shot without a reflector and another with a 50° coverage reflector. Both are 200ws. But their outputs are not nearly the same.
    Without knowing the loading capacity of the capacitors + the coverage of the reflector it is impossible to determine the gn. GN divided by the distance results in the exposure.
    Learn BCPS of your system and you can determine output. Learning the WS is like guessing output.
    you're not telling me anything i haven't known for decades, or disagreeing with anything i actually said, so why did you bother with that long-winded, condescending comment?

  7. #27

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    Re: Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

    Quote Originally Posted by maltfalc View Post
    you're not telling me anything i haven't known for decades, or disagreeing with anything i actually said, so why did you bother with that long-winded, condescending comment?
    Because your flash statements are incorrect and misleading.

  8. #28

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    Re: Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

    Quote Originally Posted by Bob Salomon View Post
    Because your flash statements are incorrect and misleading.
    work on your reading comprehension, because you didn't address my points directly or disagree with anything i said.

  9. #29

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    Re: Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

    Applies here...
    Click image for larger version. 

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    BCPS = Beam Candle Power Seconds (BCPS) Rating...
    https://www.angelfire.com/electronic...ctor/bcps.html

    Is of nil-usefulness for ANY electronic flash/strobe once a light modifier (umbrella, soft-box, beauty dish, parabolic reflector with the strobe/flash head reverse mounted and many others) has been applied to the flash/strobe head due to the how the light from the strobe/flash head is distributed within the light modifier.

    Only situation where BCPS might be a meaningful metric applies to those portable electronic strobe/flash units with a fixed reflector used as designed/delivered. Like those used by "run & gun" still image recorders folks.

    It is beyond unlikely any battery powered portable hand held "potato masher" style strobe/flash could ever hope to produce f90 at 10ft out of a BIG soft box light modifier.. To achieve that demand a truly powerful power mains strobe/flash unit..


    ~This is why a good flash meter, polaroid test or instant preview via digital is required to produce accurate exposures on digital or film. Any decent strobe/flash unit that is designed to be used with light modifiers will have the ability to adjust their light output by 1/10f-stop... which is variable BCPS..


    Bernice

    Quote Originally Posted by Bob Salomon View Post
    Originally Posted by Bob Salomon
    Because your flash statements are incorrect and misleading.
    Quote Originally Posted by maltfalc View Post
    work on your reading comprehension, because you didn't address my points directly or disagree with anything i said.

  10. #30

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    Re: Calibrating Modern Flash & Flash Bulbs & Zone Focus 4X5

    Quote Originally Posted by Bernice Loui View Post
    Applies here...
    Click image for larger version. 

Name:	Discussion.jpg 
Views:	13 
Size:	41.2 KB 
ID:	227274


    BCPS = Beam Candle Power Seconds (BCPS) Rating...
    https://www.angelfire.com/electronic...ctor/bcps.html

    Is of nil-usefulness for ANY electronic flash/strobe once a light modifier (umbrella, soft-box, beauty dish, parabolic reflector with the strobe/flash head reverse mounted and many others) has been applied to the flash/strobe head due to the how the light from the strobe/flash head is distributed within the light modifier.

    Only situation where BCPS might be a meaningful metric applies to those portable electronic strobe/flash units with a fixed reflector used as designed/delivered. Like those used by "run & gun" still image recorders folks.

    It is beyond unlikely any battery powered portable hand held "potato masher" style strobe/flash could ever hope to produce f90 at 10ft out of a BIG soft box light modifier.. To achieve that demand a truly powerful power mains strobe/flash unit..


    ~This is why a good flash meter, polaroid test or instant preview via digital is required to produce accurate exposures on digital or film. Any decent strobe/flash unit that is designed to be used with light modifiers will have the ability to adjust their light output by 1/10f-stop... which is variable BCPS..


    Bernice
    Nonsense, the output is over the angle of coverage, be it a soft dish, umbrella, soft box, back light reflector, hair light, spot light, fresnel spot, etc. it is what that head outputs over the angle covered by whatever light modifier is used, even if it’s bare bulb.

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