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Thread: Bellows Extension Factor & Flash Photography

  1. #1

    Bellows Extension Factor & Flash Photography

    Hello,

    I am starting to get a handle on using strobes with my indoor photography and I wanted to ask people in the forum how you work in your bellows ext. factor (and other exposure factors/filters etc.) into your exposure.

    Given that time won't have an effect on your exposure when using strobes, we're left with the aperture to control the exposure, how can I approach this if I want to creatively shoot with a specific aperture.

    Am I only left with the choice of increasing my flash power?

    Thanks!


    Tha

    Sent from my Pixel 4 XL using Tapatalk

  2. #2

    Join Date
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    Re: Bellows Extension Factor & Flash Photography

    If nothing moved during flash-strobe exposure, multi flash-strobe will increase effective exposure.
    Very common practice back in the days of high power required studio LF photography.


    Bernice


    Quote Originally Posted by jurgenestanislao View Post
    Hello,

    I am starting to get a handle on using strobes with my indoor photography and I wanted to ask people in the forum how you work in your bellows ext. factor (and other exposure factors/filters etc.) into your exposure.

    Given that time won't have an effect on your exposure when using strobes, we're left with the aperture to control the exposure, how can I approach this if I want to creatively shoot with a specific aperture.

    Am I only left with the choice of increasing my flash power?

    Thanks!


    Tha

    Sent from my Pixel 4 XL using Tapatalk

  3. #3

    Join Date
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    Re: Bellows Extension Factor & Flash Photography

    Hmm. Are you acquainted with Guide Number arithmetic? To get more light (brighter) on the subject, position the flash closer to it. To get less light, farther away. You can also reduce illumination by putting an ND gel in front of the flash. Or use the flash's power setting.

  4. #4

    Re: Bellows Extension Factor & Flash Photography

    Quote Originally Posted by Dan Fromm View Post
    Hmm. Are you acquainted with Guide Number arithmetic? To get more light (brighter) on the subject, position the flash closer to it. To get less light, farther away. You can also reduce illumination by putting an ND gel in front of the flash. Or use the flash's power setting.
    Yes, acquainted with the inverse square law.

    The long and short of it is, if I wanted to stick to my aperture for creative reasons, that means the only control I have is flash power correct? So if say I needed +2 stops from my extension, I can only either open up my aperture or increase flash power yeah?

    Would be interesting to see how people meter multi strobe set ups as well as I was used to single continuous light setups.



    Sent from my Pixel 4 XL using Tapatalk

  5. #5

    Re: Bellows Extension Factor & Flash Photography

    Quote Originally Posted by Bernice Loui View Post
    If nothing moved during flash-strobe exposure, multi flash-strobe will increase effective exposure.
    Very common practice back in the days of high power required studio LF photography.


    Bernice
    Yes correct, for clarity, I am just shooting still objects.

    Are the only exposure controls left just my aperture and flash power?

    So if I needed for example +2 stops from my bellows compensation that means I need to either open up my aperture or increase flash power?

    Also for multi strobe setups, which reading do you tend to follow?

    Sent from my Pixel 4 XL using Tapatalk

  6. #6

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    Re: Bellows Extension Factor & Flash Photography

    Quote Originally Posted by jurgenestanislao View Post
    Yes, acquainted with the inverse square law.

    The long and short of it is, if I wanted to stick to my aperture for creative reasons, that means the only control I have is flash power correct? So if say I needed +2 stops from my extension, I can only either open up my aperture or increase flash power yeah?
    No, you can move the flash closer to the subject. Since you're shooting still lifes, you can also fire the flash four times to get double the exposure.

  7. #7

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    Re: Bellows Extension Factor & Flash Photography

    Time letís you balance the ratio of ambient to flash exposure. It has an important effect on your results.

  8. #8

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    Re: Bellows Extension Factor & Flash Photography

    Quote Originally Posted by Dan Fromm View Post
    Hmm. Are you acquainted with Guide Number arithmetic? To get more light (brighter) on the subject, position the flash closer to it. To get less light, farther away. You can also reduce illumination by putting an ND gel in front of the flash. Or use the flash's power setting.
    Moving the strobe in or out will also change the sharpness of your light.

  9. #9
    Mark Sawyer's Avatar
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    Re: Bellows Extension Factor & Flash Photography

    Quote Originally Posted by jurgenestanislao View Post
    Given that time won't have an effect on your exposure when using strobes, we're left with the aperture to control the exposure, how can I approach this if I want to creatively shoot with a specific aperture.

    Am I only left with the choice of increasing my flash power?
    Most strobes have variable output. You can also use films of different ISOs, if you aren't committed to one film in particular. ND filters on the lens, or over the strobes, (those on the strobes can be pretty cheap plexiglass, since they're not part of the image-making optics).
    "I love my Verito lens, but I always have to sharpen everything in Photoshop..."

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