Lighting lecturer during PowerPoint presentation

[Jack Kelly]

I'm due to video a lecture soon and I'm eager to get any advice at all! I've videoed a few lectures before but I've never been entirely happy with the lighting so I'd like to try upping the game a little this time. I mostly film sit-down interviews for corporate videos.

 

The venue is a large meeting room with quite a low ceiling (i.e. there isn't a "stage" and there's no opportunity to suspend lights from the ceiling). There will be a front-projected PowerPoint presentation shown on a screen on the front wall. The presenter will be free to walk the width of the room, including in front of the projected image (i.e. it's entirely possible that they will spend some time illuminated by the projector).

 

I'm very limited in where I can position lights because my lights mustn't spill onto the projection screen. Neither must my lights distract the audience or the lecturer.

 

Ideally I'd like to illuminate the lecturer to a level similar to the level to which the projector will illuminate the lecturer if they stand in the projector's light (i.e. I'd like to fix the exposure and I don't want the image to clip horribly if the lecturer stands in front of the projector).

 

My current plan is to use two KinoFlos: one to each side of the front wall pointing directly towards the lecturer (i.e. if the lecturer was standing in the middle of the front wall facing towards the audience then he will be illuminated on both sides of his face by the two KinoFlo units). There are several reasons why I'm thinking of using this setup:

 

1. I want to use large, soft sources to illuminate the lecturers
   
2. I like the idea of using lights which wont run hot for two reason: a) safety and B) we'll have the aircon off for sound and it will get hot in there if we run bit tungstens or HMIs.
   
3. It should be relatively easy to use the doors on the kinos to prevent the light from spilling onto the projection screen or from blinding the audience too much
   

 

My biggest concern about this setup is that the level of illumination on the lecturer's face will change quite dramatically if the lecturer moves around a lot. One possibility I'm considering is building my own "Kinos" using high-frequency dimmable ballasts and I'd control the light levels on the two "kinos" from my camera position.

 

I'm shooting on a DVX100a in 16:9.

 

Any thoughts would be great!

 

Many thanks,

Jack

[Jack Kelly]

Bother, sorry - I seem to have posted exactly the same thread twice. PLEASE DO NOT REPLY HERE! Please reply to this duplicate: http://www.cinematography.com/forum2004/in...showtopic=34417