Why polarizer on white wall changes color?

Greg Voevodsky · February 11th, 2008, 02:18 PM

Thanks Ryan,

As soon as I get my new Mac - so I can offload my footage in a week or two - I will post some clips. If not, maybe I'll send you the filter or two - and we can trade them in on your new telephoto?! (I Hope).

However, the pola did work backwards - highlights were being removed - otherwise, I would have figured this out quicker. Plus the fact, everything worked both ways on my PD-150 really confused me. Thanks for your info.

Ryan Avery · February 12th, 2008, 11:33 AM

Quote:

Originally Posted by Greg Voevodsky

Thanks Ryan,

As soon as I get my new Mac - so I can offload my footage in a week or two - I will post some clips. If not, maybe I'll send you the filter or two - and we can trade them in on your new telephoto?! (I Hope).

However, the pola did work backwards - highlights were being removed - otherwise, I would have figured this out quicker. Plus the fact, everything worked both ways on my PD-150 really confused me. Thanks for your info.

I want a new telephoto too. All I can do is sit outside our engineering bay like a kid at Christmas waiting for the new adapters.

I would like to get my hands on this filter but some shots to start would do the trick. I know where Rodenstock gets thier Pol foil from and it isn't as good as ours optically so I really wonder what's going on here.

Ryan Avery
Schneider Optics

Leonard Levy · February 13th, 2008, 03:25 PM

Thanks, that is a great thing to know. i've seen this kind of pola problem before and didn't know what it was - that's with 20+ years of shooting. Never occured to me tha the pola was on backwards!

Just tested my B+W circular pola and indeed green & magenta problems in one direction - just fine in the other.

Greg Voevodsky · February 13th, 2008, 04:13 PM

Wow - guess I discover a Hollywood secret... no wonder all those music videos and 24 have funny colors - not to mention the Matrix must of had the pola on backwards the whole time. ;-)

Nik Skjoth · July 4th, 2008, 07:58 PM

PL Filters do indeed cause interesting features:

http://www.dvinfo.net/conf/showthread.php?t=125046

Ronn Kilby · January 4th, 2009, 05:40 PM

Doug Jensen, of Vortex Media ("Mastering the PMW-EX1" & "Mastering the PMW-EX3") recently sent the following to me via email (and to Avery at Schneider Optics) regarding his findings. I thought it imperative I share with the forum, if only to help some folks avoid the same frustrations:

----------------------------------------------------------------------

I came across both of the threads about color-shifts while using polarizers with the EX1 and EX3 and I thought I'd let you know what I found out after some testing.
I hope you don't mind me contacting you directly.

I have experienced the color shifting phenomena myself so I decided it was time to get it fixed. I have two 4x4 Schneider True-Pol filters and they are NOT the same. My testing shows that you DO need a circular polarizer with the EX1 and EX3.

Filter #1 was purchased in 2001and the printing on the glass says "Schneider B+W True-Pol"
Filter #2 was purchased last week from B&H and the printing on the glass says "Schneider THIS SIDE OUT Circular True-Pol"

Filter #1 causes a serious color-shift when rotated no matter which direction it is facing in the matte box.
Filter #2 does not cause a color shift as long as the glass is facing the proper direction. If the filter is mounted in the wrong direction then there is some color shifting, but not as severe as with Filter #1.

I tested both filters with my EX1 and my EX3 and as far as I can tell there is no difference at all between the two models of cameras. In other words, just as I knew they would, the EX1 and the EX3 react to the same way to both filters.

So, my recommendation to anyone looking to buy a polarizer to use with the EX1 or EX3 is that you must get a Circular Polarizer. Yes, there is a difference and it is plainly visible right on the camera's LCD -- no scopes are necessary.

I hope that helps shed some light on the debate and I only wish I had discovered this information in time to include on my DVDs. Damn!!
Feel free to pass along my testing on DVi if you would like to.

January 4th, 2009, 05:40 PM	#21
Ronn Kilby Major Player Join Date: Apr 2007 Location: Fletcher Hills, CA Posts: 211	New data on Polarizer color shift Doug Jensen, of Vortex Media ("Mastering the PMW-EX1" & "Mastering the PMW-EX3") recently sent the following to me via email (and to Avery at Schneider Optics) regarding his findings. I thought it imperative I share with the forum, if only to help some folks avoid the same frustrations: ---------------------------------------------------------------------- I came across both of the threads about color-shifts while using polarizers with the EX1 and EX3 and I thought I'd let you know what I found out after some testing. I hope you don't mind me contacting you directly. I have experienced the color shifting phenomena myself so I decided it was time to get it fixed. I have two 4x4 Schneider True-Pol filters and they are NOT the same. My testing shows that you DO need a circular polarizer with the EX1 and EX3. Filter #1 was purchased in 2001and the printing on the glass says "Schneider B+W True-Pol" Filter #2 was purchased last week from B&H and the printing on the glass says "Schneider THIS SIDE OUT Circular True-Pol" Filter #1 causes a serious color-shift when rotated no matter which direction it is facing in the matte box. Filter #2 does not cause a color shift as long as the glass is facing the proper direction. If the filter is mounted in the wrong direction then there is some color shifting, but not as severe as with Filter #1. I tested both filters with my EX1 and my EX3 and as far as I can tell there is no difference at all between the two models of cameras. In other words, just as I knew they would, the EX1 and the EX3 react to the same way to both filters. So, my recommendation to anyone looking to buy a polarizer to use with the EX1 or EX3 is that you must get a Circular Polarizer. Yes, there is a difference and it is plainly visible right on the camera's LCD -- no scopes are necessary. I hope that helps shed some light on the debate and I only wish I had discovered this information in time to include on my DVDs. Damn!! Feel free to pass along my testing on DVi if you would like to.

February 11th, 2008, 02:18 PM	#16
Greg Voevodsky Regular Crew Join Date: Sep 2006 Location: Portola Valley Posts: 105	Thanks Ryan, As soon as I get my new Mac - so I can offload my footage in a week or two - I will post some clips. If not, maybe I'll send you the filter or two - and we can trade them in on your new telephoto?! (I Hope). However, the pola did work backwards - highlights were being removed - otherwise, I would have figured this out quicker. Plus the fact, everything worked both ways on my PD-150 really confused me. Thanks for your info.

February 13th, 2008, 03:25 PM	#18
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	Thanks, that is a great thing to know. i've seen this kind of pola problem before and didn't know what it was - that's with 20+ years of shooting. Never occured to me tha the pola was on backwards! Just tested my B+W circular pola and indeed green & magenta problems in one direction - just fine in the other.

February 13th, 2008, 04:13 PM	#19
Greg Voevodsky Regular Crew Join Date: Sep 2006 Location: Portola Valley Posts: 105	Wow - guess I discover a Hollywood secret... no wonder all those music videos and 24 have funny colors - not to mention the Matrix must of had the pola on backwards the whole time. ;-)

July 4th, 2008, 07:58 PM	#20
Nik Skjoth Regular Crew Join Date: Jul 2007 Location: Cph Denmark Posts: 136	PL Filters do indeed cause interesting features: http://www.dvinfo.net/conf/showthread.php?t=125046