Lighthouse Effect sweeping across a room. Night/Int.

[Ollie Downey]

Hi guys,

I have a commercial coming up, set in a cliff side apartment at night, where the light from a nearby lighthouse intermittently sweeps across the room. It's a studio build, we're shooting on the Alexa and I wondered if anyone had done this, or had any tips on how to achieve it.

At present I'm thinking some sort of Xenon fired into a revolving mirror cube.

Any help, tips, advice or ideas very very welcome!

Thanks in advance

Ollie

[Adrian Sierkowski]

You're on the right track-- but the real question is how much of the room do you want it to light up and how far away can you position it?

[Ollie Downey]

Hi Adrian, the set is still being designed so to a certain degree the ball is in my court. I'm guessing the room will measure approx 20 ft by 20ft and I can position the source the other side of the stage if need be. Still waiting on floor plans but I'm guessing 20ft away from the set windows wouldn't be a problem

[John Holland]

At that distance and shooting with a Alexa i dont think you would need something as powerful as a Xenon maybe a Source 4 or something in that line .

[Adrian Sierkowski]

A bit will depend on how you want the beam to look. Were It me, I'd maybe go for a more powerful source and something like a large 6x6 stippled reflector, so it's directional but softer a bit to really fill in the whole room. Maybe you could rig it to a lazy susan which just spins by hand. Probably still wouldn't use a Xenon; maybe a 5K or a 4K HMI depending on what color temp you want and the how bright. I'd start with a larger source one could scrim down if need be.

[Toby Orzano]

Did this on location once, day for night where the windows would be in frame. Thick ND on the windows, I think at least three layers of .9. Then a 6K PAR for the lighthouse sweep. We started with a spot lens but it wasn't quite enough punch through all that ND so we ended up going sans lens. Unfortunately I can't find the footage online, but I recalled it looked pretty good. There was probably a better light for the job but it was part of a feature and the 6K was in our standard package and they wanted to avoid day-playing additional gear. In any case, we just panned across, then tilted down and panned back below the window to the starting point and panned across again, no spinning reflectors or anything.

 

Since you have the luxury of being on a stage, maybe a 5K or 10K Molebeam projector, depending on what interior levels you are balancing to?

 

I guess it will also depend on what you are seeing. Do you just see the beam swipe through, perhaps edging a subject; or do you actually see the wall where the beam hits and watch the spot swipe through, maybe even front-lighting a subject as it crosses? And how tight or wide are the shots?

 

For the aforementioned feature, we did shoot in and around the actual lighthouse. I was surprised to learn that the actual fixture in the lighthouse was just a 150w (if I recall correctly, though it was definitely something low like that) incandescent bulb with a couple plastic fresnels spinning around it. Lighthouses are meant to be seen, not to actually illuminate anything around them, but alas audiences are still looking for that gag. The good thing is that you have some artistic license as to how you want your beam to look.

Edited March 5, 2014 by Toby Orzano