Posted by Greg Melton on 01/27/07 22:52

On 27 Jan 2007 13:57:07 -0800, "AEngineerDU" <AEngineerDU@gmail.com>
wrote:

>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


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

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