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Author Topic: Cross Polarized Light 4 Macro  (Read 4039 times)

SPW11

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Cross Polarized Light 4 Macro
« on: June 25, 2007, 10:00:02 am »

Hello all... My first post here.  I'm in way over my head, but I'm going to ask anyway because I want to get the best result I possibly can.

I was watching LLVJ 16 and the interview with Bill Atkinson where he described his set up for "Within the Stone" using polarizing filters on both the light source and on the lens... Cross Polarization?  He took shots with and without the lens polarizing filter of a color chart and the differences were astounding.

I'm wanting to take similar types of shots of my agate collection w/ a Cannon 30D and 100mm f2.8 macro, but I'm not sure about the polarization filters I need.  I'm intending to use SoLux lighting and fixtures so I'm going to have to fabricate some kind of mechanism to hold the filters on the source lights.

Would those need to be linear polarization filters since there in more or lens a fixed postion?

I'm assuming the filter on the lens would need to be a circular polariztion filter because of the AF?

Is there some geometric relationship between the polarizing filters on the light source and the lens that has to be maintained?  In other words will I have the flexabilty to move the lights around to different locations relative to the camera?

Any thoughts on this set up... What I'm trying to do and/or what filters I should be looking at would be greatly appriciated!

Thank You!

Steve Wheeler
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Jim White

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Cross Polarized Light 4 Macro
« Reply #1 on: June 25, 2007, 10:34:26 am »

Have a look at this article, see if it helps.

http://www.naturescapes.net/042004/wh0404.htm

Jim
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SPW11

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Cross Polarized Light 4 Macro
« Reply #2 on: June 25, 2007, 10:48:03 am »

Quote
Have a look at this article, see if it helps.

http://www.naturescapes.net/042004/wh0404.htm

Jim
[a href=\"index.php?act=findpost&pid=124772\"][{POST_SNAPBACK}][/a]


Thanks Jim!  I will check this article out.

Steve
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SPW11

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Cross Polarized Light 4 Macro
« Reply #3 on: June 25, 2007, 11:53:19 am »

A question about the above article...

Quotes..

"The plane of polarization of the film on the flash head must be 90 degrees or perpendicular to the plane of the polarizer on the lens for maximum effect."

"Notice that the films on each flash are aligned so that the light leaving both flashes is in the same plane of polarization."

I can see that the polarizing films on each of the flash units are aligned.  

What I can't see is that the plane of polarization of the film on the flash head is 90 degrees or perpendicular to the plane of the polarizer on the lens.  To me that statement indicates the polarizing film (thus the flash units) must be at 90 deg to the lens which doesn't make sense to me.  (Sorry... I don't know how to paste the pic of the camera/ flash set up from the article to this post.)

If using a circular polarizing filter on the lens and linear film on the light source is it that the filter films on the sources need to be "radial" to the circular filter and parallel to each other?  

What am I missing here?

Steve
« Last Edit: June 25, 2007, 12:07:51 pm by SPW11 »
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