Help lighting with monolight with barn door and diffuser gels

Discussion in 'Lighting Equipment' started by bob_estremera, Jan 4, 2009.

  1. Been researching the heck out of a simple, one-light traveling setup for on location single-sitter (2 at the most) portraits.
    A monolight with 150w/s will be the source.
    Pretty much arrived at using a shoot-through for any applications that require soft, big light.
    Simplicity, ability to place the light close to subject and portability are my criteria for this aspect of lighting.
    But, I'm also attracted to the William Mortensen technique that requires, a 'starting point' of placing a smaller reflector as close to the lens axis as possible.
    My thinking is that I might achieve something very close to this by replacing the umbrella with a set of barn doors and adding diffusion gels, one or two, so that I can place the light, at various degrees of softness, very close to the lens axis. I would experiment with placement from that starting point.
    What quality of light can I expect to achieve with the barn door/diffusion gel?

    Thanks, Bob
  2. A barn door is not a diffusion device, it merely provides a means to keep the light off areas at the sides of the strobe coverage.
    Diffusion gel will not make your light source any larger than the diameter of the gel itself (typically 7"), your shoot through umbrella will make your light source as large as the umbrella (typically 36-48"). They are not interchangable for your purposes.
    For portraiture, you typically want a large light source close to the subject, so the light "wraps around" the subject, making soft light-shadow transitions. Diffusion gel won't help you achieve this.
    I'd suggest sticking with the shoot through umbrella, or better yet a softbox.
  3. Bob,
    I have to pretty much agree with Charles. A diffusion gel placed over a regular head will generally just smooth out the light and spread the angle of coverage. Nevertheless, and all theory aside, if your flash projects an uneven, harsh light (and many units do), the gel will make it look a bit softer. The gel won't change the shadow edge characteristics much though. If your goal is to sculpt the face with a harder, more directional light, then your idea has some merit. By adding a gel to your light, you can extend the feathering area at the edge of the light beam, and if you are good at using the beam edge in conjunction with barn doors, you can create really cool retro-looking portraits with it. However, if you are positioning the light near the camera position, and consequently not raking it across the face, you won't be able to use that feathering. I'm not sure why one should start with a hard source close to the camera, though I'm sure there is some reason. It seems to run counter to current lighting wisdom. But, then again, rules were made to be broken, right?
    Oh, and one more thought: If you are not using a separate fill light with that barn-door contraption, you will be left with very deep shadows and, perhaps, excessive contrast. With the shoot-through, at least, you can fill the shadows nicely with the light reflected from a flat on the side opposite the light.

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