Using an umbrella/flash

Discussion in '35mm Cameras' started by James Bass, Jan 21, 2004.

  1. James Bass

    James Bass Guest

    I just picked a 42" silver umbrella to mount onto my lightstand & I was
    wondering what is the standard distance between the flash (SB-28DX) & the
    umbrella ? Is there some sort of formula ?

    -tia

    james
     
    James Bass, Jan 21, 2004
    #1
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  2. James Bass

    Kevin Backs Guest

    Hi James,

    There is no formula to speak of. Instead, you should position the
    umbrella so that it is completely lit by the flash, but so that no
    light spills out around it.

    What does that mean?

    Start with the umbrella set as far out as possible. If you have a
    modelling light, you can use that to check how much of the umbrella is
    lit.

    If light spills around the umbrella -- you'll see light from the flash
    unit on the walls and/or ceiling and/or floor -- move the umbrella
    closer until there is no spill-over.

    If the whole umbrella (or at least almost al of the umbrella) doesn't
    get lit by the flash unit (or modelling light), then the umbrella is
    too big for the reflector you're using. You may be able to get a
    reflector that has a wider aim.

    Light spill is more of a problem that a too-big umbrella. With a
    too-big umbrella, you'll still be reflecting back all of the light
    that comes from the flash, it just won't be as diffuse as if it was
    being reflected from the whole umbrella, and you can adjust just how
    diffuse the light is, by moving the umbrella closer to the flash --
    this will change the size and intensity of catchlights in model's
    eyes, and highlights). If you have spill, then light that is
    reflecting from the walls, floor and ceiling may (probably will)
    change the quality of light hitting your subject.

    Since we use things like umbrellas, reflectors, gobos, barn doors,
    soft boxes, etc, to have more control over the quantity, quality and
    direction of our lights, it makes sense that we probably don't want to
    add random light that's being bounced from the ceiling, walls and
    floor. OTOH, you may find that controlled spilling of light around
    your umbrella may give you an effect or look that you want.

    HTH



    -Kevin Backs

    my email:
    kbacks @at@ rogers .dot. com


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    Kevin Backs, Jan 21, 2004
    #2
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