Just wondered how many of you are using Polarizers - tried them - and what one do most of you recommend? I tried a circular "Hoyer" one and couldn't see a difference so took it back for a refund. How good are the more expensive - warming polarizers?

I'm looking to darken the blue sky as much as possible without making the foreground too dark. Any tips?

There are two types of polarizer: linear and circular. The circular is what you should use with DV cameras. You want to get on of the adjustable ones so you can dial in the amount of filtration you want.

I never shoot outside without one, they are great for darkening skies, saturating colours and reducing the harsh contrast inherent with video.

Any Japanese made polarizer will do the job you want, avoid Korean made ones as the glass is second rate. I have a couple of different brands, Hoya and Kenko, and they both do the job well. If you can afford to spend a little more get a Tiffen.

There was probably nothing wrong with the polarizer you returned. You have to understand what polarizers do and when they will work.

1. They darken areas of the sky that are 90 degrees from the Sun. The effect falls off the closer one gets to the axis of the Sun (draw a line from the Sun to you . . . that's the axis of interest).

2 They will also 'remove' some reflections from glass and other shiny surfaces (Like water) as long as the light that is causing the reflection is itself, polarized. Doesn't work for light bulbs unless you place a polarizing filter on them too.

The adjustment mentioned by Adrian is that most polarizers can be rotated on their mount. That allows you to dial-in what you want from no effect to maximum effect.

If you have a camera that focuses by rotating the front of the lens (very few permanently attached lens today) then you will have to first focus and then adjust the polarizer.

A polarizer is something to use with some caution as it can make scenes look overly color saturated. As with all filters, use with some amount of caution.

thanks for your replies. I tested the same polarizer, but 49mm, on my still camera to compare and I didn't notice any change on my pd150 when fiddling with the iris and ND filters.

I'm not sure what effect or difference you were expecting to see when 'fiddling with the iris or with ND filters', as that would primarily make a difference only to the exposure.

You would expect to benefit from a polarising filter if your subject included reflections off water, for example. By rotating the filter you might largely eliminate these reflections. Don't anglers use polarising sunglasses so they can see fish more clearly beneath the surface?

And you would certainly see a marked difference to the blue of the sky ... ah, but in Wales, isn't the sky always the colour of Tupperware? :-)

There was a series of architectural programmes on TV in the UK recently in which a polarising filter had pretty obviously been used. The skies were so blue you'd never have thought they were in the UK at all.

Al

Yes, that's the effect I'm after.

Looking at the polarizers at BHPhotoVideo.com, it is quite hard to make a decision on how much to pay. What polarizers do all you have and how much?

Once again in this tread the circular polar is being advised as necessary. This is not true, a linear does a perfect job for video, at least as good as a circular. Another misconception is that "the light causing the reflection should be polarized itself". All light hitting (electrically) non conductive reflective surfaces get linearly polarised, also the light from lightbulbs. The amount of polarisation (thus the degree to which reflections can be suppressed) depends on the angle of incidence and refractive index ratios. Complete polarisation will be at an incident (and reflection) angle of about 50degree for water and glas reflections.

Andre,

Correct me if I'm wrong, but I thought you couldn't use a linear polarizer with 3 chip DV cameras due to the use of a light splitting prism to seperate the RGB beams and send them to their respective CCD.

This is an on going debate that will not be resolved in the near future. However, Canon does make a three filter set for the XL1/S and the Circular Polarizer is what Canon sells in the kit. I hope this helps.

Jeff

For the umteenth time, I use a linear on my VX2K and TRV20 and have never had a problem. Before you discount Andres advive , you may want to check his credentials.

I have the utmost respect for Andre, but on this matter our opinions differ.

Jeff

Brian,

That is why I started the post with "correct me if I'm wrong". I understood that there was a technical reason that linear polarizers did not work as effectively with DV cameras. Maybe I worded it incorrectly. If you have anymore to say on this issue I'd appreciate it you'd contact me directly via e-mail so the thread doesn't turn into another DV vs film debarcle.

I personally prefer the Tiffen Water White UltraPol 4x4 filter. It is the best Polarizer you can find. I have both the standard version as well as the "warm" 812 version.

http://www.tiffen.com/camera_filters.htm

- don

I own the 3 piece Canon filter kit for each lens I own and don't shoot outside without the polarizer. I shoot a lot of aircraft and can get a nice medium blue sky if I want it. One thing I've found is that I have to do a white balance after each adjustment of the filter or I get a purple sky, but no biggie.

I got bored one day and decided to stack 2 to 3 of the polarizers in bright sunlight and got a cool effect similar to the beach scene in the movie "Contact" (where she meets her father). The sky looked very dark, but most everything else was "moonlit". Old film trick but it looked cool.

G

Adrian,
Your concern about the effects of the color splitting system is a real one at first view. There is indeed a theoretical risk of getting slight polarisation effects in the small spectral parts where the dichroics change from transparant into reflective (between red and green, and between geen and blue), but this problem is beeing solved by chosing the right angles and some other optimisations. Same problems had to be solved for LCD projectors using color splitting prisms..See e.g. http://www.ee.ust.hk/~eekwok/publications/2000/AO_2000_39_168.pdf . If your cam would have polarisation effects on its own, just think what would happen if you rotate your cam when pointing to the sky or any other reflective surface...
Greg,
Indeed you can play with 2 stacked polars as a (strong) "ND" filter (first one must be linear). And if the first one is a circular one (the other is of no importance) you can even change the color balance in the scene. This is an ilustration of the fact that the retarder used for "depolarization" in circulars doesn't depolarize but just creates two orthogonal linearly polarized components which energies are wavelenght dependent.

To add some non-technical stuff here...........

I've mentioned a few times before that in our films & footage, we use nothing but Hoya Circular Polarized filters on the XL1s.

Big blue skies, and what a way to film fish in their natural habitat. It suppresses a huge portion of the reflection of light from the surface of the water.

On accident (wasn’t trying for the effect) I filmed an almost surreal shot where the sun was off to the left of the lens view about 30 degrees, spotty but thick clouds, water moving down river, my partner fly fishing in the center of the frame………

It was one of those things you will never recreate until you figure out how to control Mother Nature.
After panning another 30 or 40 degrees to the right on the tripod, the effect was gone……..

In my neck of the woods……circular polarized filters on the XL1s are a “must have” in your bag of tricks.

Let's put this in a context that everyone understands, money.
Buy a $20 linear and try it, if it doesn't work exchange it for a $40 circular. N'uff said?

(prices bases on a 58mm tiffen from B&H)

Sure, lets put it in context. Someone spends $3500 USD for an XL1. He goes on a once in a lifetime trip or shots a project for a client that can't be reshot. Then finds out if he had spent $20 more he could have gotten better shots. That's 1/2 of 1% of the cost of the camera. The $20 all of a sudden seems insignificant in comparison with the cost of the camera, a major trip or impressing a major client. Risk any or all that for a measly $20. Not after what I've already invested.

Jeff

I have a B+W Circ Pol, It uses the newer F-Pro format B+W has adopted, slimmer than the older style. It has an adjustment ring Adrian spoke of, but I haven't seen any noticeable difference when using the ring...

<<<-- Originally posted by SyneticDV : It has an adjustment ring Adrian spoke of, but I haven't seen any noticeable difference when using the ring... -->>>

Same here....no visible difference (to me anyway)

Circular and linear polarizers are manufactured to rotate in a circular manner. This enables you to rotate the filter in relationship to the angle of reflectance. When looking at the blue sky through a polarizer (either circular or linear) you will see the sky darken and lighten as you rotate the filter. The rotating mounting ring (not the threads) is how you adjust the degree of polarization. References to circular or linear relate to the manner in which the light is polarized, not the rotating mount that both types share.

Complete details on polarizing filters can be found by using the search function as this topic has been discussed in length before.

Jeff

I have a Heliopan linear polarizer. When I hold it up to the sky and rotate the front of it, there is a very visible difference. The difference is easily noticable through the viewfinder as well.

Regarding circular polarizers:

Be sure to have the right side of the filter facing the lens. The Lee circular polarizing filter is packaged with a slip of paper that's easily overlooked. It says, "Circular Polarisers will only work correctly in one direction. Please ensure that the filter is positioned in the holder so that the printed surface faces away from the lens."

If you keep the proper side away from the lens the difference is easily noticed. If the wrong side faces the lens the difference is almost non-existent. This mistake is easily made with square filters that are slipped into matte boxes.

Other than that, circular and linear polarizers do function the same way. They both have to be rotated or oriented properly to block out unwanted reflections and/or make the sky more dramatic.

Dean Sensui
Base Two Productions

Greg Vaughn, or anyone else who might know!

you stated:

((( ....I own the 3 piece Canon filter kit for each lens I own and don't shoot outside without the polarizer. I shoot a lot of aircraft and can get a nice medium blue sky if I want it. One thing I've found is that I have to do a white balance after each adjustment of the filter or I get a purple sky,)))


Lets say you were using your filters and were using a monitor with it, like a flat Nebtek monitor on the XL1s, would you be able to see the effect on the monitor? Or would you be shooting blind (considering you have a B&W viewfinder)

thanks

The effects of a polarizer, being primarily a luminance issue (the sky is not so much getting bluer as darker when the pola is applied), can be viewed with a black and white viewfinder. If you have zebras enabled, you can actually see the zebras diminish as you rotate the pola.

Charles,

But can the effects be seen on a monitor? Lets say you use a different filter, or maybe use several at once and get a weird hazzy effect, will it show up on the monitor?

thanks

Indeed Charles, the sky gets darker because part of the scattered (and polarized under certain viewing angles) blue light gets absorbed by the polar. The cloudless sky looks bleu because of the scattering of sunlight on different molecules in the atmosphere (air, dust,.. ). If this scattering would not exist, the sky would look perfectly black (like it is for the astronautes)
Of couse Gateway, the effect can be seen on a monitor.

For what it's worth, Panasonic Tech says either circular or linear polarizers will work with their DV cams.

Cheap filters can cause a color shift. It was discussed a little here http://www.dvinfo.net/conf/showthread.php?s=&threadid=3021&highlight=ND+color+Tiffen I think the word purple is a bit strong, but I have seen colors change with the use of poloraizers. I used a poloraizer on a very cold (-20F) day, very clear (little pollution) and it turned the sky very, very dark blue.

Jeff

Just a thought on why some folks are not seeing a difference with polarizer use.

If the camera is in a fully Auto mode, it will adjust exposure and white balance as the filter is being rotated. In Auto mode it can be difficult to discern when the polarizer is affecting the scene.

Shooting in manual will best show the polarizer's effects.

Ron Johnson
Portland, OR

Here's a link to George Kalemanis' polafilter FAQ:
http://w3.one.net/~georgek/htmldocs/uvfilter.htm#polq2

And here's a short quote: <<If you use a standard linear polarizer with cameras that use auto-focus and/or auto-exposure, you may have problems. This filter may also cause trouble with manual cameras, if you're using TTL light measurement. >>

Further down he stresses the fact that you may have problems, and thus also may not.

This is the understanding that I had; I believe I've seen and heard similar opinions a number of times. So I was confused to read in this thread that the only difference is the 20 dollars.
Tor

This article relates to photographic apps. Video does'nt require circ polars. Use good (coated) polars, and these are mostly circ polars.