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Polarizing filters for EX-1

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Jay Curlee
Polarizing filters for EX-1
on Dec 15, 2009 at 6:27:11 pm

Is a polarizing filter a good idea for handheld shooting musicians under a canopy with bright sky and ocean reflection in the background?

If so which filters would you recommend? I am using Vortex Media's Doug Jensen's basic picture profile suggestion (from their handbook and DVD). Should I tweak those settings to accommodate the filter?

TIA,


Jay Curlee

JC Communications
Makers of Rocking the Boat: A Musical Conversation and Journey
http://www.rockingtheboatmovie.com


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Daniel Startek
Re: Polarizing filters for EX-1
on Dec 15, 2009 at 8:53:09 pm

I use a Tiffen 4x4 polarizer filter UPC 049383018837 and it works great for bright skies and water without affecting everything else. Make sure you use a linear NOT a circular polarizer. White balance AFTER you put it on because I have noticed that it affects the EX far red idiosyncrasy (reds in the black).



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Jay Curlee
Re: Polarizing filters for EX-1
on Dec 15, 2009 at 9:03:07 pm

Actually, I have just read that we can ONLY use circular filters in the EX-1. My concern is that I am running and gunning and can't be white balancing more than once every five minutes or so.



Jay Curlee

JC Communications
Makers of Rocking the Boat: A Musical Conversation and Journey
http://www.rockingtheboatmovie.com


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Michael Pruitt-Bruun
Re: Polarizing filters for EX-1
on Dec 15, 2009 at 11:28:50 pm

i don't know why you'd need to get a new balance every 5 minutes. if you're going in and out of doors without warning, save an indoor and an outdoor balance. if it's really that hectic, you could use auto.

anyway if it's a screw mount polarizer make sure it's a slim profile (it'll say something like that in the product description), or you won't be able to use it under the standard lens hood.


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Jay Curlee
Re: Polarizing filters for EX-1
on Dec 15, 2009 at 11:41:04 pm

I will only be outside when using the polarizing filter. The first issue is linear vs circular filter. I was wondering how sensiitive the filter would be to light angle. I read on another forum that the linear filter caused major color shifts.

Jay Curlee

JC Communications
Makers of Rocking the Boat: A Musical Conversation and Journey
http://www.rockingtheboatmovie.com


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Michael Pruitt-Bruun
Re: Polarizing filters for EX-1
on Dec 16, 2009 at 12:13:08 am

i've only ever used screw mount, circular polarizers. they need to be aligned when mounted. in the field, the quickest method i've found is to use zebras and rotate the filter til i see the smallest area of zebras in the viewer. if you're dealing with reflections rather than glare, you can just rotate the filter til you see the least amount of reflection. but both methods should get you to the same alignment.

i'm not familiar with color-shift issues. but that is not to say that you shouldn't keep asking about it. i did find that for some reason i didn't get as much joy out of the polarizer with this camera as i have with others, and i'm not sure why. it didn't give me the rich blue skies that i recall getting with polarizers previously. maybe it was the polarizer i was using, but i never experimented further because i returned it as it wouldn't fit under the lens hood.


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Derek Reich
Re: Polarizing filters for EX-1
on Dec 16, 2009 at 5:54:56 am

Hi, Jay
Daniel was incorrect.... you MUST use a circular polarizer on the EX1 and EX3. A linear polarizer will most definitely cause color shifts as it is rotated.

You should not need to tweak any of your camera settings when using a polarizer, and the results will be pretty visible. It should be quite helpful in reducing reflections on the water.

There are several good polas to choose from, I'm not sure if you are using a matte box or just need a 77mm screw-in. Schneider, Tiffen, B+W are a few good ones that jump to mind.

Happy shooting!



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Jay Curlee
Re: Polarizing filters for EX-1
on Dec 16, 2009 at 7:55:35 am

The daytime shooting conditions are typical very sunny, requiring use of the eyepiece. I am hoping that I don't have to do too much rotation of the filter when I go from one side of the stage to the other.

I was looking at a Tiffen kit that has a UV filter as well. I have been living dangerously with the lens exposed to the elements before now. I am going to keep a clear, polorizer, or UV filter on the lens henceforth.

Maybe I should look for a hoodman shade for the lcd screen, too.

Thanks for confirming what I read elsewhere.





Jay Curlee

JC Communications
Makers of Rocking the Boat: A Musical Conversation and Journey
http://www.rockingtheboatmovie.com


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Clint Fleckenstein
Re: Polarizing filters for EX-1
on Dec 16, 2009 at 2:57:24 pm

I have used the CP filter from one of my still camera lenses on our EX1 and EX3 and love the results. If your angle relative to the sun changes, just rotate the filter. You will have to leave the matte box off to make this adjustment. I also put UV filters on both cameras (and all my still lenses) immediately to protect the front element of the lens. UV filters fit under the matte box just fine but do not work with the Sony bayonet mount wide angle adapter.

You do get a color shift from a polarizer as it tends to "warm" the picture perceptibly. How pronounced this effect is may depend on the ambient light. When shooting outdoors this winter I noticed it a lot, since there's more blue light bouncing around. On a golden sunset shoot it's only visible in the blue/green areas of the shot.

Cf


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Derek Reich
Re: Polarizing filters for EX-1
on Dec 16, 2009 at 4:37:20 pm

The amount of polarization you will get is relative to your angle to the sun. Ideally, a 90 degree angle will yield the most visible results (with the sky, anyway). As you approach either 180 degrees (either the sun is directly in front of you or directly behind you) the results will be less effective. This does not apply as much to reflective surfaces, only the darkening of the sky. You really just need to play with it and see what works best for you.

I have never used a UV filter on any video or still camera in 30 years of professional photography. I suppose they are useful for protecting your outer element from a possible scratch or something hitting the lens, but I've always felt that if you pay good money for a decent lens, why put anything in front of it that you don't absolutely need? And, if you buy a cheap UV filter, you could negate the optical quality you just paid good money for. If you do use one, make sure you get a good one! You should also pay attention to your VF with respect to the sun. Be very careful to avoid ever having the sun shining directly into your VF, or you will damage the viewfinder itself. The magnifier works just like a magnifying glass under the sun, and can not only damage the components of the viewfinder, but actually melt the plastic housing. ALWAYS keep the VF pointed down or covered when not shooting.

I'm not aware of any significant color shift when using a polarizer unless it's a 'warm' polarizer with a warm tint added like an 812. All a polarizer should do is remove reflected light on surfaces or from particulates in the air. This will often result in increased saturation without the reflected light bouncing back to your camera.

One last thing..... are you aware of the IR issue with these cameras? The EX cameras (and many other CMOS sensor cameras) suffer from some level of infra-red or near infra red contamination. If you ever have had a black article of clothing in your image turn magenta or brown, that's what you're seeing. It most commonly affects black synthetic clothing, which has become a real pain to wedding photographers for obvious reasons. At the moment, the only solution is an IR cut filter. There are two currently available which work very well but each has it's own limitations. One of these filters, the Schneider 486 is what is known as a 'hot mirror' filter and MUST be the first filter light hits. This means that if you are also using a polarizer, the polarizer must be BEHIND the 486 or the 486 will not work. The Tiffen does not have this limitation and can reside in front or in back of the pola, but this filter loses about a stop of light. If you're outside, this probably wouldn't be an issue, or if you're not seeing the contamination, then you don't need to worry about it at all until you do.


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Daniel Startek
Re: Polarizing filters for EX-1
on Dec 16, 2009 at 8:07:48 pm

You are right. I saw a video on YouTube about polarizers on the EX-3 and got circular and linear mixed up! But I've been using my Tiffen 4x4 polarizer (which Tiffen says is linear) for months and not noticed the color shift other than the far red effect in the blacks. This can be corrected with an initial white balance.



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Clint Fleckenstein
Re: Polarizing filters for EX-1
on Dec 16, 2009 at 10:23:35 pm

I'll defer to you guys on the color shift thing, since I'm no expert. In my photography experience as a hobbyist, I notice a difference that I have attributed to a lot of reflected blue light (from snow, etc) that gets filtered out. I wouldn't say that there is a color shift inherent to the filter. Any correction would be appreciated :)

Cf


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Tim Kolb
Re: Polarizing filters for EX-1
on Dec 17, 2009 at 4:14:50 am

A polarizer, when properly utilized, shouldn't shift colors, it removes glare.

To oversimplify this somewhat...coins can only go through a coin slot in one angle...it's a slot. Coins pushed at the slot that are rotated so they won't go through can't pass. Light waves tend to modulate at all sorts of angles...a polarizer is like introducing a coin slot.

The effect is usually most pronounced with shiny, reflective surfaces at, or around a 30 degree angle to the camera...rotating the polarizer will take a massive specular glare off a new car, or allow you to see through the store window by removing the reflection of the street behind you.

The color shifts can happen when you use a linear polarizer on a 3 chip camera. There is a system of reflective/transparent surfaces that separate the light into the proper wavelengths to pass to the proper sensor. These surfaces are themselves a sort of polarizer.

When you take two sets of polarized sunglasses (or two polarizer filters for that matter) and look through both of them while turning them in opposite directions, you'll see that when they are at a 90 degree angle to each other, they're opaque. They block all light.

When a linear polarizer does it's thing and passes the polarized light to the prism in the camera, the angle of the polarizer combining with the angles of one or more of the camera's internal mirror surfaces will act like a multiple polarizer, and since the surfaces that allow or reflect light to each sensor are at different angles, the angle of the polarizer will interact with different wavelengths, therefore different sensors, therefore different colors...creating color shifts as the wavelengths of light will vary in strength from one sensor to another.

A circular polarizer is not named for its roundness. A circular polarizer takes the polarized light and sends it to the camera "twisting" like a corkscrew. Even though the light is still polarized, since it's angle is now rotating onto the sensor/prism assembly, no imbalance in color strength is created.

As far as Infra Red...that's a Ex1/Ex3 thing that has little to do with polarization. The camera is simply sensitive to IR and does create some reddish hues in the blacks. Tiffen has an IR filter developed specifically for the purpose of neutralizing this issue.




TimK,
Director, Consultant
Kolb Productions,


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Don Greening
Re: Polarizing filters for EX-1
on Dec 17, 2009 at 7:42:27 am

[Tim Kolb] "Tiffen has an IR filter developed specifically for the purpose of neutralizing this issue. "

...and it's called the Tiffen T1 IR filter. It's worth about $140.00 ea. CAD and it's a "must have" for anyone using an EX1, EX1R or EX3.

You can read a great (but short) article about the issue here:

http://provideocoalition.com/index.php/aadams/story/tiffens_goes_into_produ...

- Don



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Jay Curlee
Re: Polarizing filters for EX-1
on Dec 17, 2009 at 3:30:51 pm

Tim and Don, thanks for these very detailed and useful posts. Do you recommend stacking the T1 and polarizing filters? I realize that they won't fit under the lens shade.

Jay Curlee

JC Communications
Makers of Rocking the Boat: A Musical Conversation and Journey
http://www.rockingtheboatmovie.com


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Michael Palmer
Re: Polarizing filters for EX-1
on Dec 17, 2009 at 3:44:56 pm

No one ever wants to stack filters, and the Tiffen T1 is really only used with tungsten lighting, while a pola is best used for a front lit sky. I don't think anyone would stack these filters.

Stacking filters can cause strange flares, reflecting from the back filter to the front filter, generally not a good idea.

Good Luck
Michael Palmer


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Mark Bolding
Re: Polarizing filters for EX-1
on Dec 18, 2009 at 8:12:36 pm

."and it's called the Tiffen T1 IR filter. It's worth about $140.00 ea. CAD and it's a "must have" for anyone using an EX1, EX1R or EX3."

I was under the impression that the far red problem had been corrected on the EX1. Anyone run into it yet with the new camera?

Thanks

mb


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Don Greening
Re: Polarizing filters for EX-1
on Dec 18, 2009 at 8:34:27 pm

Mark,

The blog at AbleCine has a pretty good article showing the differences when using the Tiffen T1 IR on the EX1. The far red issue is a lot better on the newest version of the EX but it's not perfect. The PMW-350 looks pretty good though. You can see the article here:

http://blog.abelcine.com/2009/10/29/tiffen-t1-ir-filter-and-the-ex-cameras/

- Don


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