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-   -   I just got a polarizing filter for my XL2 and I have a few questions... (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/33079-i-just-got-polarizing-filter-my-xl2-i-have-few-questions.html)

Matthew Cherry October 6th, 2004 06:14 PM

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!

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.


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