FORUMS: list search recent posts

polarized light sources

COW Forums : Lighting Design

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Bob Cole
polarized light sources
on Feb 12, 2012 at 4:42:40 am

Has anyone had experience using polarized light sources to reduce reflections from shiny and irregularly-surfaced objects? I believe I recall reading about still photographers who used polarized lights (not just a filter over a lens, but polarized sheets over the lights themselves) for copy photography.

Thanks.

Bob C


Return to posts index

Chris Wright
Re: polarized light sources
on Feb 12, 2012 at 8:29:32 am

the expensive ones you can rotate to vary the intensity to the point that glass becomes invisible, although they often bring back some reflections so it doesn't look too weird, like mime acting behind doors.


Return to posts index

adam taylor
Re: polarized light sources
on Feb 13, 2012 at 9:08:28 am

i remember years ago using a polarised light source together with a polarising filter on the lens to show stress patterns in Laboratory glass.

The lens would be rotated to 90degrees from the light source and then when the glassware was handled, the stress patterns were clearly visible through the camera.

Not quite the answer to your question, but its one worth dropping in the memory banks for another day!

Adam Taylor
Video Editor/Audio Mixer/ Compositor/Motion GFX/Barista
Character Options Ltd
Oldham, UK

http://www.sculptedbliss.co.uk
My YouTube Animations Page


Return to posts index


Mark D'Agostino
Re: polarized light sources
on Feb 13, 2012 at 4:36:51 pm

We purchased a sheet of Rosco's polarizing gel a few years back for a project. We needed to reduce glare on a table without it changing as the camera panned. It worked nicely but like a lens polarizer you'll lose about 1-1/2 to 2 stops from your light source. Here's a link to a source for that: http://www.filmandvideolighting.com/pofish19x20i.html

Mark D'Agostino
http://www.synergeticproductions.com


Return to posts index

Ken Maxwell
Re: polarized light sources
on Feb 15, 2012 at 8:38:36 pm

Interesting enough, a number of years ago I was directing in television. We bought a couple of the Rosco polarized sheets that Mark referred to. We trimmed and mounted one of them into a blank circular baby fresnel scrim frame, built a motor driven bracket to hold and rotate the polarizer in front of a baby and with it back-lit a regional weather map that was drawn on a 4'x5' sheet of ground glass. We then randomly cut out weather symbols from the other Rosco sheet.
When the weather person placed the symbols (with double-faced tape) onto the map they randomly blinked and no one could figure out how we made the little symbols blink. Kind'a fun for those days.


Return to posts index

Russell Calkins
Re: polarized light sources
on Feb 16, 2012 at 12:05:07 am

I remember seeing a doc shoot on a train car they used the rosco gel to polarize all the windows. Then they slapped a polarizer on camera. When they were shooting at night/dusk/beautiful sunset, they left the camera polarizer open. During mid-day/harsh conditions, they flipped the polarizer on camera and just knocked down all the windows. I thought it was about the coolest setup i'd ever seen. They balanced inside/outside sources for all conditions in about 2 seconds with a simple turn on camera.


Return to posts index


Bob Cole
Re: polarized light sources
on Feb 16, 2012 at 1:35:42 am

Great (though expensive) solution if they gelled all the windows! Do you recall the name of the doc? I'd like to see it.

Did they have any problem with uneven lighting out the windows when panning the camera?


Return to posts index

Russell Calkins
Re: polarized light sources
on Feb 16, 2012 at 2:29:42 am

I think i read about it on a DP forum.

Here's some footage...i don't understand a word, it's in french for canadian television.







Notice how her skin tone is almost the same value as the sky outside. The plates on the table are blowing, but outside is nicely controlled.

for the newbies, this is the product i'm talking about:
http://www.rosco.com/us/video/roscoview.cfm

on this shoot i'm pretty sure they used the panels (not the rolls), and then just rigged them to the outside of the moving train.


Return to posts index

Bob Cole
Re: polarized light sources
on Feb 16, 2012 at 3:15:30 am

Great example. Question for the gurus: how do you think they augmented the natural light for these shots?

(quick correction to my first reply here) The Rosco website says that the ambient light falling from the window onto the interior is cut by one stop, which seems pretty good - largely preserves the window-light effect, which heavy ND of course would kill.

Another question: Rosco specifically advises using the Rosco polarizing camera filter since it is matched to the RoscoView. Is that advice valid?


Return to posts index


Russell Calkins
Re: polarized light sources
on Feb 16, 2012 at 3:27:34 am

this isn't the article i read the first time...that one had a behind the scenes video that i watched. But in this thread, the DP says they lit the interiors with just 4 Ringlite minis.

http://www.cinematography.com/index.php?showtopic=37887


Return to posts index

Todd Terry
Re: polarized light sources
on Feb 16, 2012 at 4:09:14 am

It's a cool way to have very good control over window lighting... however I think the DP was a bit heavy-handed with it in the train example. It's too even, so that the result looks fakey like a process shot. For interiors with windows in the scene, the most natural-looking results usually come about when the exterior windows are at least a stop (or even two) hotter than the interior. That more replicates what the eye is used to seeing. Without any window gelling of course the windows would be a lot hotter, maybe as much as seven or eight stops... but keeping them a couple of stops hotter is more what the brain interprets as natural-looking on screen. This product could do it, but I'd crank down the polarizing a bit.

I don't know bout the cost of the panels, but the rolls of this material are, as someone above mentioned, quite expensive. I have not priced it in a long time, but it used to be more than a thousand bucks a roll.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



Return to posts index


<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]