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-   -   Polorizing Lamps? (https://www.dvinfo.net/forum/photon-management/138989-polorizing-lamps.html)

Phillip Palacios December 4th, 2008 07:23 PM

Polorizing Lamps?
 
looking through the rosco catalouge, i noticed the following filter:
Rosco Polarizing #7300 Filter you can find it on B&H (still a sponsor here right?)
i am well versed in the benefit of using polarizing filter for light entering my lens, but i am not familiar with a polarizer in front of a lamp...
what are the benefits / situations when you would want this?

would this be good for rim lighting objects with some metallic parts? to knock down the glare of those parts without losing the 1-2 stops of light for the whole scene that a filter in front of my lens would?

phil

Phillip Palacios December 5th, 2008 08:38 AM

i know my spelling and grammer are not that great, but no responses? hmm.... this is obviously not a much used filter.
anyone?

Christopher Witz December 5th, 2008 10:01 AM

I've used pol sheets on lights when shooting stills of paintings.... removed the glare form the gloss varnish on oil paintings.... a real life saver. They still need to be used along with a pol on the lens.

Josh Laronge December 5th, 2008 10:33 AM

pol sheets won't remove reflections from metal. They are great for shooting special effects with clear plastic items.

Photoelasticity - Wikipedia, the free encyclopedia

Seth Bloombaum December 5th, 2008 08:54 PM

Polarizing filters are commonly found on copy stand lamps for still & video, for the reason that Christopher mentioned.

Usually copy stands position the lights at 45 degrees to minimize reflections to the lens, but when you have oils or acrylics, or other subject that isn't just flat, reflections can be a real problem. Pol on the lamps and lens almost totally tame the problem.

Another approach is to completely flatten the light by using a small translucent tent over the subject, this is commonly done for shiny objects (coins, jewlery, etc.)

So far as I know, you're not going to find Pola gel in use on sets & locations - I don't think there are accepted applications for it outside the above. The double of polarized source and pola on the lens can do some real magic, but you lose a lot of stops in the process.

Nino Giannotti December 6th, 2008 08:22 AM

Usually polarizing gels on the lights need to be used in conjunction with the polarizing filter on the camera in order to be most effective.

Jon Fairhurst December 6th, 2008 01:40 PM

A cool use of pol gels is for shots of a car at night. Polarize the headlights. Rotate the polarizer on your lens until you get the right balance between the headlights and the rest of the scene.

We did some greenscreen work with cars. The polarizing filter on the lens was enough to remove/balance the glare from the auto glass and reflections off the body. This is critical because most of the reflections are green!

I say start with a polarizing filter. Keep gels at the ready, when the filter alone isn't enough. That way you can polarize almost any light source - not just that one special light.


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