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Mark DAgostino
Double Polarizing
on Dec 9, 2016 at 8:06:31 pm

Our company recently built a new regional corporate headquarters. The walls are all glass looking out over the city and the harbor. All the conference rooms are full glass walls, like fishbowls. I'd like to use the view as a background for interviews but do not have the fire power to overcome the level on a sunny day, nor the time to play with various NDs. I have a lot of film experience and have worked with NDs to solve this issue for years.
I remember there being a double polarizer kit from someone that seemed like a nice solution for this quick and dirty balancing; polarizer on camera, polarizing gel on window. It makes the level of ND correction highly adjustable. I know I can buy the gel separately and use with my polarizers but I'm simply curious about finding the "kit" and am using it specifically for interviews, mostly MCU to MS. Anyone know know about this?
Thanks!

Mark D'Agostino
Video Producer
Creative Media Productions - Exelon
Baltimore, MD
MacPro,2.7 Ghz 12-Core Intel Xeon E5, 64GB 1866 Mhz DDR3 ECC, AMD FirePro D700 6144MB, AJA Io XT, Yosemite 10.10.1


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Todd Terry
Re: Double Polarizing
on Dec 9, 2016 at 8:48:34 pm

Never heard of that... but it does sound like a fairly semi-genius idea.

I'd be very curious to see if anyone else has heard of this, or done it.

Seems to me that if the gel is readily available... there's no need for a "kit" containing both the gel and the lens polarizer... especially considering there is such a wide range of filter sizes and types that would need to be covered (for example, I would need square 4x4 polarizers for my matte box, like most cine lenses mine have no filter threads).

Interested to hear.....

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Erik Anschicks
Re: Double Polarizing
on Dec 10, 2016 at 7:23:37 am

Yes, it's called the Rosco View. Essentially it is a double-polarization system, where you put a specific gel on the window and then use the specific View glass filter to rotate and darken/brighten the light outside WITHOUT affecting the light levels inside and on subjects.

Here's a link to it's usage with examples: http://www.thehurlblog.com/cinematography-online-rosco-view-new-frontier-to...

I haven't personally used it, the main downside of the system seems to be that the gel component is absurdly expensive and doesn't appear to be widely available in a size practical for anything but the smallest of windows ($246 on BH for a 10'x17" roll). Perhaps Rosco or some of their dealers might sell larger ones directly, but they aren't exactly making that easily known. The example link above includes a photo of what the author says is a 4x4' of the gel in a standard frame so it must be possible, assuming all info is correct. I also don't think that it would be a very practical item for rental houses to stock with their standard gel expendables, due both to gel cost and the fact they'd have to supply multiple glass filters in varying sizes on top of that for the system to work.

It's one of those things that I always want to try out but never really get around to putting in the effort to do so since it's not easily acquirable for testing.


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Todd Terry
Re: Double Polarizing
on Dec 10, 2016 at 8:10:53 am

Yes, I knew it would be expensive.... actually that is a fair bit cheaper than I figured it would be, although that size available from B&H isn't wide enough to be super practical. I would say that if 4x4s are available, as the blog says, that would be a minimum, and even those would be useful only a fraction of the time.

I do think it is interesting that in the blog they also talked about using it on a light source, with the author saying "HMIs, which can never dim, have a way to dim now." I'm not sure where the author gets that... most if not all modern HMIs with electronic ballasts will indeed dim (I know that mine do). Many will dim to 50% and of course all can have their outputs dimmed with conventional wire scrims.

Now if they made this stuff in a big wide roll.......

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Erik Anschicks
Re: Double Polarizing
on Dec 10, 2016 at 2:49:18 pm

I think what he meant by "HMI's don't dim", is that you can't dim them all the way down to nothing the way you can with a different source like tungsten. He was talking about it within the context of a lighting cue where he needed the light to go completely out so none hit the talent's face during the shot, live and in camera. This is/can be commonly done with a tungsten or LED bulb because they dim completely to zero but since HMI's only dim about a stop to 50% of output or so, you couldn't do the same thing with them.

As for putting it on the light itself, this is apparently one of the main uses for this gel in the still-photo world, specifically to eliminate reflections of the light and specular highlights while shooting things like paintings for art reproduction. I had never thought about doing this before, but it totally makes sense. If a subject is lit at all, you're going to see SOME sheen or a reflection of the light/light source itself, and a double-polarization system should indeed make that disappear so the subject looks as flat and "un-lit" as possible.

In the motion-picture world, I could certainly see SOME possibilities for this, like in product or tabletop work perhaps, or in specialized situations like the author found himself in. Otherwise, I don't think it would work as well in general in our realm because that would cut the light levels a LOT, since you're putting a pola gel on source itself as well as from using a Pola in front of the lens.

I'm also not an expert on the physics of light, but I would imagine the light waves would bounce around too much for this to be effective if shooting through diffusion or bouncing, so it would really only work (well) using lights raw.

But an interesting trick to have up your sleeve in certain situations for sure!


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Bob Cole
Re: Double Polarizing
on Dec 10, 2016 at 3:52:05 pm

re still photography: way back when, my photography mentor had a regular job shooting silver flatware and bowls. Reflections were not just inevitable; they were part of the appeal of the objects. So he built a white, translucent tent, now a commonly available item.

re movies: I had to film a lot of very shiny and bag-like packages on a motorized lazy susan. It was impossible to avoid reflections, so I tried the Rosco lighting gel and a polarizer. It helps. But I avoided it, because it imparted a slight purple sheen to the highlights, which would have "reflected" badly on the printing process we were trying to promote.

For your interview application, this sounds like one of those good ideas that doesn't actually work in the end. But if it does, you are a hero, and you need to share your solution with us, please!

Bob C


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Erik Anschicks
Re: Double Polarizing
on Dec 11, 2016 at 4:57:33 am

[Bob Cole] " But I avoided it, because it imparted a slight purple sheen to the highlights, which would have "reflected" badly on the printing process we were trying to promote."

Did you use the actual Rosco View glass Pola, or a different one like from Tiffen, Schneider, etc...? I ask because Rosco specifies that using any other glass Pola in front of the lens other than their specially-made View one will result in unwanted color shift. Of course that could be marketing-speak, but if it's specifically engineered to play well with the gel, I'd buy that. Wonder if there are any tests out there...

[Bob Cole] "For your interview application, this sounds like one of those good ideas that doesn't actually work in the end."

One of my gaffers said almost exactly that when I explained this system to him years ago...and while I've never had hands-on experience, I'm inclined to agree. I wonder too if it would still be effective at varying angles of windows in relation to the camera given how light waves have to be shaped in a certain way to most effectively utilize cross-polarization. Sounds more and more like this is one of those "once in a blue moon"-esque methods where the circumstances have to be JUST right.


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Bob Cole
Re: Double Polarizing
on Dec 11, 2016 at 12:26:55 pm

[Erik Anschicks] " Rosco specifies that using any other glass Pola in front of the lens other than their specially-made View one will result in unwanted color shift. "

Thanks! I used a non-Rosco polarizer. Either I missed that warning, or they didn't warn us at the time. This was about 3 years back. It will work with a non-Rosco polarizer, and that highlight sheen I mentioned was not terrible - just inappropriate for a job where accurate color rendition was essential. (To be clear: my situation was different from the OP's - I was polarizing a light source, not a background view.)

Back to the OP... I totally sympathize with your desire to use that view, and you're brave to try. I too am from Baltimore, and occasionally have the same problem: a fantastic harbor that can be great for a still photo, but problematic for movies because it changes so fast with the weather and clouds. The light has to be just right for the view to "read" as beautiful, and when the light changes, the whole tone of the scene changes dramatically, very quickly.

I would advise: use one of the cheaper gelling solutions (I've used Rosco #210 .6 Neutral Density, which comes in a 4x25' roll) over the big windows. Then grab your wide shot when it looks good, and shoot the rest in MCU. Then, hope the CEO doesn't want you to be able to repeat the scene whenever he's available.

Or shoot a "plate" of the harbor on a great day, and green screen the interviews? What do the rest of you folks advise? Not about Rosco ND gel, but about the beautiful window situation. These companies are paying a heap of money to locate with these breathtaking views, and they like being able to use them.

Bob C


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Erik Anschicks
Re: Double Polarizing
on Dec 10, 2016 at 2:53:56 pm

I think what he meant by "HMI's don't dim", is that you can't dim them all the way down to nothing the way you can with a different source like tungsten. He was talking about it within the context of a lighting cue where he needed the light to go completely out so none hit the talent's face during the shot, live and in camera. This is/can be commonly done with a tungsten or LED bulb because they dim completely to zero but since HMI's only dim about a stop to 50% of output or so, you couldn't do the same thing with them.

As for putting it on the light itself, this is apparently one of the main uses for this gel in the still-photo world, specifically to eliminate reflections of the light and specular highlights while shooting things like paintings for art reproduction. I had never thought about doing this before, but it totally makes sense. If a subject is lit at all, you're going to see SOME sheen or a reflection of the light/light source itself, and a double-polarization system should indeed make that disappear so the subject looks as flat and "un-lit" as possible.

In the motion-picture world, I could certainly see SOME possibilities for this, like in product or tabletop work perhaps, or in specialized situations like the author found himself in. Otherwise, I don't think it would work as well in general in our realm because that would cut the light levels a LOT, since you're putting a pola gel on the source itself as well as from using a Pola in front of the lens.

I'm also not an expert on the physics of light, but I would imagine the light waves would bounce around too much for this to be effective if shooting through diffusion or bouncing, so it would really only work (well) using lights raw.

But an interesting trick to have up your sleeve in certain situations for sure!


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Erik Anschicks
Re: Double Polarizing
on Dec 10, 2016 at 2:54:50 pm

Damn, sorry about the double-post!


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Mark DAgostino
Re: Double Polarizing
on Dec 13, 2016 at 2:24:16 am

Thanks everyone for your input. The possible use for this certainly is limited and the specific use I am planning for probably is the ideal one for this. My subjects will be seated in front of a window and I can control the angle. I've done years worth of green screen, not desired here and straight nd on windows, changing background light means changing nd; not practical.
Fortunately the cost is okay for me. I plan to contact Rosco and quiz the heck out of them before considering a purchase. I'll keep you all apprised of the outcome.
Happy Holidays!

Mark D'Agostino
Video Producer
Creative Media Productions - Exelon
Baltimore, MD
MacPro,2.7 Ghz 12-Core Intel Xeon E5, 64GB 1866 Mhz DDR3 ECC, AMD FirePro D700 6144MB, AJA Io XT, Yosemite 10.10.5


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