On Jan 27, 4:42 pm, "AEngineerDU" <AEnginee...@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.
>
> 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
Jim,
The traditional way of doing this is with a spot light on the
lecturne. Barn doors are used with broad beamed light, they are
nothing more than a shade that blocks the light. Some auditoriums have
spots on either side of the screen, some unfortunately only have a
bank of lights in front, short of having some bulbs taken out there is
not much to do with that type of room layout.
You could put a spot light on a stand and light the lecturne that way,
but to look right it needs to be high up, and 15-20 foot stands are
expensive, not to mention the price of a good spot light. The other
thing a light of that sort does is inhibit the speaker, especially if
they move around the stage.
Digital projectors tend to be bright so take a light reading on one
presentation, we average, not whte of black backgrounds and a light
reading around the lecturne, your hand is a good object to use, see
how they fall you might be surprised. Another good thing is that
digital camcorders tend to have good light sensitivity.
Good luck
Tom
Similar Threads
