Lighting speakers next to screen - Equipment Advice

Discussion in 'Professional Video Production' started by AEngineerDU, Jan 27, 2007.

  1. AEngineerDU

    AEngineerDU Guest

    In several courses I teach students make presentations standing next
    to a projection screen (computer projector). I'd like to get a record
    of the presentations in which both what they're projecting and the
    students are visible. It seems to me this ought to be possible by
    having the students stand next to the screen and lighting them with a
    luminaire that has a cutoff so that they're illuminated, but not the
    screen. From my reading the device for this kind of control is called
    a "barn door".

    We'll be recording several days of presentation at a time using a
    digital camcorder (Panasonic PV-GS39).

    My questions:

    1) Does anyone have experience doing this kind of work, and if so,
    does what I propose make sense?
    2) Do you have recommendations for the kind of lights and barn door
    (or other device) I should purchase. I don't have a signficant budget
    for this so price matters.

    Thanks

    Jim Mitchell
     
    AEngineerDU, Jan 27, 2007
    #1
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  2. AEngineerDU

    Greg Melton Guest


    The easiest and most effective way is with an "ellipsoidal" or
    commonly referred to as a "leko" light. It has built in shutters and a
    focusable lens. The farther away the light, the smaller degree lens
    you should use. You can make the spot smaller with a circle pattern
    which is inserted in the housing.

    New, these lights average about $300 $ 375 plus the lamp.
    Used on ebay about half of new.
    Rentals about $15 to $20 a day.

    Barn doored lights will only work properly when they're close to the
    background that's affected. You'll never get a sharp edge from a
    distance.

    Greg Melton
     
    Greg Melton, Jan 27, 2007
    #2
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  3. AEngineerDU

    David McCall Guest

    There are many things you can do, but the most effective thing I've found
    is to put the light on the opposite side of the screen from the speaker.

    This creates a side light from the same side of the presenter as the light
    from the screen itself, so it looks more natural than front light. When the
    presenter is speaking to the audience he will only be half lit, but you will
    be able to see him. When he looks over to toward the screen he will be
    nicely lit. You can add a second light to help fill the other side.

    Presenters sometimes walk right in front of the screen, and a light well
    to the side will still work, while a light from the front will not.

    If the speaker is on the right side of the screen then put the light in a
    similar
    position, but on the left side of the screen. This puts the light source at
    about
    90 degrees to the screen, and any stray light will affect the image much
    less
    than if it was from the front. This light would want to be 8'-12' above the
    floor
    (depending on how big the screen is).

    You will need some way to control the light so that it doesn't get in the
    audience's eyes, or on the screen. This is what you use "barndoors" for.
    If you don't have barndoors on your light then you will have to improvise.
    You can buy a product called Blackwrap which is aluminum foil painted
    black. I suppose you could paint your own (use high temperature paint).
    You can attach it with spring clamps. Another poster has already suggested
    using an ellipsoidal reflector light (Leko). They have 4 nice shutters that
    allow
    you to shape the light beam fairly precisely. They are mostly used in
    theater
    an clamped to pipe battens. You will need to come up with a way of
    mounting it.

    David
     
    David McCall, Jan 28, 2007
    #3
  4. AEngineerDU

    Greg Melton Guest

    If stand mounted, a "bail block" or "tvmp adapter" instead of a clamp
    mount is needed. Should be mounted on a c-stand or better.

    http://www.bhphotovideo.com/bnh/con...181&is=REG&addedTroughType=categoryNavigation

    Greg
     
    Greg Melton, Jan 28, 2007
    #4
  5. This is as much an issue of proper camerawork as lighting. You need to
    run the camera on manual iris control for starters.

    First expose for the screen to get a good image, then lock the iris to
    that, and begin
    to light your talent. Aim the light from 45 degrees off to one sid eor
    the other, so as not to dazzle them when
    they address their audience.

    Another way to go is a little more complicated: record the screen
    stuff using a
    dedicated closeup camera onthe screen or a scan converter on the
    computer
    output, and a camera just for the speaker, expoesed right for them,
    then combine
    the two in post on an editing system. More effort and expense but
    also
    a more polished look.
     
    nobody special, Jan 28, 2007
    #5
  6. AEngineerDU

    Stan Guest

    }In several courses I teach students make presentations standing next
    }to a projection screen (computer projector).
    (snip)
    }2) Do you have recommendations for the kind of lights and barn door
    }(or other device) I should purchase. I don't have a signficant budget
    }for this so price matters.

    Well, if it's just for classroom use, I used a film-strip projector
    with a "fake slide" made out of thin metal, with a hole cut in it that
    lit just the speaker and a bit of the podium. The film-strip projector
    acts as an ellipsoidal light, but less intense (and very cheap).
    This would not be suitable for a video you plan to distribute.

    Stan.
     
    Stan, Jan 28, 2007
    #6
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