I just got a polarizing filter for my XL2 and I have a few questions... at DVinfo.net

Matthew Cherry · October 6th, 2004, 06:14 PM

Not sure if I'm posting this in the right place (I seem to have a problem with that), but here goes...

I just picked up a Schnieder polarizing filter for the XL2. Wow, what a difference and this is just in my living room! It seems to do some pretty neat stuff, although it also makes things darker. I'm going to set up some lights now and experiment a bit, but I was wondering if any of you had some hits or tips for working with the filter, or if you knew of a good resource for info on this.

Thanks!

Jimmy McKenzie · October 6th, 2004, 07:28 PM

If it's a circular polarizer with the outer ring that spins, this is moving the orientation of the angled elements of the filter to knock down glare. When outside and shooting into a car window this is the way the camera "sees" inside. Also when the sun is bouncing off a poolside shot the filter behaves the same way. To a lesser extent, you will have interesting reults on blue sky days with big cumulus clouds. Does a nice job of killing the haze without absorbing a ton of stops. The result is more blue and less contrast.

Matthew Cherry · October 6th, 2004, 07:39 PM

Do you ever use one in-doors? I think I like it.

Jeff Donald · October 6th, 2004, 09:09 PM

All polarizers (linear and circular) have an outer rotating ring. The terms circular and linear refer to the method in which the light is polarized. Polarizers are used to saturate colors and reduce or eliminate reflection. Rotate the outer ring until the reflection in the surface is reduced or eliminated. Rotate the ring until the sky becomes the darkest or reflective surface (leaves, grass, almost any surface) becomes darkest. Some material will not work with polarizers, such as unpainted metal and snow. Polarizers will reduce light transmission by 1 to 2 stops in most cases. Polarizers have limited use indoors, mostly reduce reflection.

Kevin Triplett · October 9th, 2004, 10:15 PM

Polarizer filters are very handy -- another use is to increase the amount of reflection in a surface, like a window, if you want to capture the reflection of someone, say that person is looking out the window. In this case, light the person well so that they stand out from the darker background and then use the polarizer to get the brightest reflection of the person. You can also fog the glass to increase the reflection.

Jim Sofranko · October 12th, 2004, 03:50 PM

The effect of the polorizer for exteriors is determined by the camera's postion to the sun. It works best when the sun is ninety degrees and least when the sun is to your back. Hope this helps.

Matthew Cherry · October 12th, 2004, 04:09 PM

Thanks guys. I noticed that it also works as an ND filter. Is it wrong (or rather stupid) to use it in this fashion if lighting permits?

Jim Sofranko · October 12th, 2004, 05:04 PM

You can use it that way but I wouldn't on a regular basis. You must be careful as you can get color abberations from using it in artificial light especially flouroscent. Best to get a set of ND's if you want to have that kind of stop control.

Barry Green · October 12th, 2004, 06:47 PM

Don't use a polarizer as an ND filter. Typically you use an ND filter when outdoors, and a polarizer will affect your video differently depending on where the sun is relative to your shot. You may find that one shot has a deep saturated blue sky and the next shot you'll have a pasty white sky... difficult to intercut.

Jeff Donald · October 12th, 2004, 07:30 PM

Polarizers can also create problems with the sky, for example. If you're using a lens towards the WA focal lengths, the sky on one side of the scene can be much darker than the other side. The wider the angle of view, the more pronounced the effect.

Jim Sofranko · October 12th, 2004, 10:09 PM

Jeff - good point and very true as a result of the nature of polorization. It is the same reason that the position of the sun is important as light is polorized according to it's directionality.

I recently noticed the effect you mentioned and was surprised how pronounced it could be.

But polroizers are a great and critical tool to control your image making. It is my first filter of choice for video.

I've been using a Zhang rotating pola in my 4x4 Vocas mattebox. It is an interesting filter because it is a round filter which rotates within it's own 4x4 frame. The Zhang has a small dial on the corner to dial it in. That makes it very fast and easy by not having to turn the entire filter stage.

As to the difficulty of using it outdoors for the sky. I believe it depends on the material you are shooting and what control you may or may not have. By this I mean that in a narrative you can shoot the wide with the polorizer and use it if possible in the tighter shots to help the blue in the sky. If the sky isn't as blue in tighter shots this can be painted in any sophisticated post facility.

If you shooting material that has a series of sky shots then matching can be difficult. And the pola can be overdone but I vastly prefer to use it to match skies than not.

October 6th, 2004, 06:14 PM	#1
Matthew Cherry Major Player Join Date: Sep 2004 Location: Stamford, CT United States Posts: 212	I just got a polarizing filter for my XL2 and I have a few questions... Not sure if I'm posting this in the right place (I seem to have a problem with that), but here goes... I just picked up a Schnieder polarizing filter for the XL2. Wow, what a difference and this is just in my living room! It seems to do some pretty neat stuff, although it also makes things darker. I'm going to set up some lights now and experiment a bit, but I was wondering if any of you had some hits or tips for working with the filter, or if you knew of a good resource for info on this. Thanks!

October 6th, 2004, 09:09 PM	#4
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	All polarizers (linear and circular) have an outer rotating ring. The terms circular and linear refer to the method in which the light is polarized. Polarizers are used to saturate colors and reduce or eliminate reflection. Rotate the outer ring until the reflection in the surface is reduced or eliminated. Rotate the ring until the sky becomes the darkest or reflective surface (leaves, grass, almost any surface) becomes darkest. Some material will not work with polarizers, such as unpainted metal and snow. Polarizers will reduce light transmission by 1 to 2 stops in most cases. Polarizers have limited use indoors, mostly reduce reflection. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

October 12th, 2004, 07:30 PM	#10
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Polarizers can also create problems with the sky, for example. If you're using a lens towards the WA focal lengths, the sky on one side of the scene can be much darker than the other side. The wider the angle of view, the more pronounced the effect. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

October 6th, 2004, 07:28 PM	#2
Jimmy McKenzie Major Player Join Date: Jan 2004 Location: Waterloo Ontario Posts: 721	If it's a circular polarizer with the outer ring that spins, this is moving the orientation of the angled elements of the filter to knock down glare. When outside and shooting into a car window this is the way the camera "sees" inside. Also when the sun is bouncing off a poolside shot the filter behaves the same way. To a lesser extent, you will have interesting reults on blue sky days with big cumulus clouds. Does a nice job of killing the haze without absorbing a ton of stops. The result is more blue and less contrast.

October 6th, 2004, 07:39 PM	#3
Matthew Cherry Major Player Join Date: Sep 2004 Location: Stamford, CT United States Posts: 212	Do you ever use one in-doors? I think I like it.

October 9th, 2004, 10:15 PM	#5
Kevin Triplett Mad Scientist Join Date: Jan 2002 Location: Austin, TX Posts: 47	Polarizer filters are very handy -- another use is to increase the amount of reflection in a surface, like a window, if you want to capture the reflection of someone, say that person is looking out the window. In this case, light the person well so that they stand out from the darker background and then use the polarizer to get the brightest reflection of the person. You can also fog the glass to increase the reflection.

October 12th, 2004, 03:50 PM	#6
Jim Sofranko Major Player Join Date: Mar 2004 Location: West Shokan, NY Posts: 217	The effect of the polorizer for exteriors is determined by the camera's postion to the sun. It works best when the sun is ninety degrees and least when the sun is to your back. Hope this helps.

October 12th, 2004, 04:09 PM	#7
Matthew Cherry Major Player Join Date: Sep 2004 Location: Stamford, CT United States Posts: 212	Thanks guys. I noticed that it also works as an ND filter. Is it wrong (or rather stupid) to use it in this fashion if lighting permits?

October 12th, 2004, 05:04 PM	#8
Jim Sofranko Major Player Join Date: Mar 2004 Location: West Shokan, NY Posts: 217	You can use it that way but I wouldn't on a regular basis. You must be careful as you can get color abberations from using it in artificial light especially flouroscent. Best to get a set of ND's if you want to have that kind of stop control.

October 12th, 2004, 06:47 PM	#9
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	Don't use a polarizer as an ND filter. Typically you use an ND filter when outdoors, and a polarizer will affect your video differently depending on where the sun is relative to your shot. You may find that one shot has a deep saturated blue sky and the next shot you'll have a pasty white sky... difficult to intercut.

October 12th, 2004, 10:09 PM	#11
Jim Sofranko Major Player Join Date: Mar 2004 Location: West Shokan, NY Posts: 217	Jeff - good point and very true as a result of the nature of polorization. It is the same reason that the position of the sun is important as light is polorized according to it's directionality. I recently noticed the effect you mentioned and was surprised how pronounced it could be. But polroizers are a great and critical tool to control your image making. It is my first filter of choice for video. I've been using a Zhang rotating pola in my 4x4 Vocas mattebox. It is an interesting filter because it is a round filter which rotates within it's own 4x4 frame. The Zhang has a small dial on the corner to dial it in. That makes it very fast and easy by not having to turn the entire filter stage. As to the difficulty of using it outdoors for the sky. I believe it depends on the material you are shooting and what control you may or may not have. By this I mean that in a narrative you can shoot the wide with the polorizer and use it if possible in the tighter shots to help the blue in the sky. If the sky isn't as blue in tighter shots this can be painted in any sophisticated post facility. If you shooting material that has a series of sky shots then matching can be difficult. And the pola can be overdone but I vastly prefer to use it to match skies than not.