polorizing filter

[fargogogo]

Does anyone use a Polorizing filters? Do they make much difference? What about a Spherical Polorizing filter?

Thanks.

[Ken Tanaka]

Yes, they are very useful and do make a difference. Use the 'Search" button and you'll locate many, many posts on the subject. BTW, I think that you meant "circular" polarizer, not "spherical".

[Dylan Couper]

What Ken said. Although I've never had the need for mine, there is comfort in knowing its there in my camera bag if I need it.

[fargogogo]

thanks.

I had tried a search and came up with nothing...but I had spelled polarizing wrong. :(

[Jeff Donald]

Dylan,

Try shooting with it. It makes the colors more sturated or vibrant. You want deep blue skies, that's one way get them. It does a whole lot more than just take glare off of glass.

Jeff

[Dylan Couper]

Jeff, I have used it outdoors for skies. I meant that I've never needed it for it's glare/reflection reduction. I should have been a little more clear, since it is a two purpose item.
It does do a really nice job bringing out the blue in the sky.

[Charles Papert]

I "audition" a polarizer for many situations working outside, some of which are not obvious reflection issues. We all know that they do a fantastic job of removing reflections in glass when shot at a 45 degree angle (i.e. perfect for windshields, not so great for side windows of a car), but they can also help tremendously when dealing with high contrast exteriors such as shooting down a street with the sun in front of you (backlit). In this instance, a certain amount of the brightness of the street itself may be due to glare and the polarizer will knock down the intensity, helping achieve a less hot image. Likewise shooting around water, it can help bring the bright white appearance down to a more photographable blue/green. Too much polarization can deaden an image, so it's good to think of a polarizer as not just an "on-off" filter, but something that allows one to dial in exactly as much effect as desired. Going back to that windshield, it may be nice to see a little reflection of the exterior world (trees, puffy clouds in sky etc) so a partial polarization may work great. It's often helpful to hold the pola up to your eye and rotate it, watching the effect, then once the desired angle is found you transfer it to the camera at that angle.

[Dan Uneken]

It is also cool as a sort of ND filter when you don't want the 7 stops knocked off that the XL-1 (if you have one) does for you.

[Charles Papert]

Yes Dan, good point. Most polas will cut between 1 2/3 and 2 stops of light.

[Don Berube]

I may sometimes use an UltraPol on a subject to saturate skin tone and allow me to open up the iris which can sometimes help to throw the background out of focus. It's also a handy filter to knock out shiny reflections on people's faces when there is not makeup available.

[fargogogo]

In what situations would you use a circular polarized filter as opposed to a "regular" one?

[Jeff Donald]

Circular polarizer offer a stronger affect than linear polarizers. Blue skies bluer, green grass greener etc. Some cameras may also require the circular type to avoid interference with auto focus or other performence related factors. There are strong arguments on both sides as to if they are required or not. Circular polarizers are also more expensive. Inexpensive polarizers sometimes don't even work. Try it before you be sure of the stores return policy. I recommend B + W, Heliopan and Nikon as better circular polarizers. Tiffen, Hoya and other name brands are in a lower tier in my opinion.

Jeff

[Charles Papert]

Jeff:

I have understood that circular polarizer are designed for cameras that incorporate a beam splitter or light meter/auto-focus system that may be fooled by the polarized light, and they essentially depolarize the transmitted light after the initial polarization. In other words, they don't create any more effect than a linear polarizer...?

Incidentally, Tiffen has introduced a stronger pola (Ultra-Pol) to compete with the Tru-pol from B&W/Schneider. It's definitely more potent than their earlier offering.

[Don Berube]

The Tiffen Water White UltraPol compares easily and very favorably with the B&W TruePol. It is being used on many sets now, in addition to many other Tiffen filters - at least that is what is being reported by shooters out in the Burbank and Hollywood area,,, not as clear what the filter of choice is from "the other Hollywood" on the other side of the country, not as many reports coming in from there.

Due to the big demand for the UltraPol, Tiffen has decided to make it available as a screw-on filter.

I have some B&W filters as well and I like them a lot, in addition to some Schneider filters which I like as well, and I would not hesitate to lump my Tiffen filters into that same category.

[Jeff Donald]

Over the years I've done side by side film tests with linear and circular polarizers. One test was to evaluate the reduction of reflection from glass. The circular polarizer clearly reduced the amount of reflection over the linear in that test. Since the affect of saturating colors comes from reducing the polarized light reflected off grass, buildings etc. it could be assumed that the affect would be noticeable in all scenes. The tests I did of average scenes involved exposing 35mm slide film and using the same exposure, just switching filters. The test slides show an increase in saturation from linear to circular. However, the tests were subjective in that the sampling of filters was too small and densitometer readings were not made of the slides. If it's not a difference between polarizers what could cause the affect? The circular polarizer my require a higher filter factor. It could reduce exposure maybe a 1/3 of a stop and the manual exposure setting did not compensate for the factor. The exposure change of 1/3 stop less light could saturate the colors in the slides. If I have time in the next month or so I may repeat the test a little more objectively. However, the comparison of reflections on glass are clearly superior with a circular polarizer.

Jeff