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Polarizer filter factor?


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#1 Hunter Hampton

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Posted 19 December 2008 - 05:46 PM

I should know this but I don't... Is it 1/3 to 2/3 stop? Thanks.
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#2 Adrian Sierkowski

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Posted 19 December 2008 - 06:05 PM

IIRC my tiffen is 2 stops. . .
Might be filter specific though, give a call to your manufacturer, or an e mail to 'em.
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#3 Tom Hepburn

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Posted 19 December 2008 - 06:45 PM

Good question. I have a circular polarizer and Tiffen said,
for those numbers the f-stop compensation can vary between 11/2 and 2
f-stops.

?

Hoya filter

tiffen
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#4 Adrian Sierkowski

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Posted 19 December 2008 - 06:54 PM

Well split the difference, 1 and 2/3 stop ;)
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#5 Hunter Hampton

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Posted 19 December 2008 - 07:12 PM

Its a tiffen linear I think so 1 2/3 sounds good then. I'm shooting 7201 so im sure I will be ok.

This is my favorite forum because of people like you guys! ;) Thanks.

Edited by hunter richards, 19 December 2008 - 07:12 PM.

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#6 Andrew Brinkhaus

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Posted 19 December 2008 - 07:31 PM

You could always note the difference when placing your polo over your meter in incident mode.

Edited by Andrew Brinkhaus, 19 December 2008 - 07:31 PM.

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#7 K Borowski

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Posted 19 December 2008 - 08:07 PM

1-1/2 to 2 stops sounds right, but also, keep in mind that I believe it depends on the orientatio of the polarizer.

In other words, it is shot-specific, not a set factor.


Without an in-camera meter (do these even exist on any pro MP cameras?) you'd actually need to meter through a polarizer oriented comparably, I think.
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#8 Jonathan Bowerbank

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Posted 19 December 2008 - 10:08 PM

Which is why you have to shake up that pola with each camera setup. Take it out, note the position, then slap it back on the lens.
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#9 John Brawley

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Posted 19 December 2008 - 11:43 PM

I should know this but I don't... Is it 1/3 to 2/3 stop? Thanks.


It's variable but i usually go for 1 + 2/3 for a tiffen and 2 stops for a tru-pol.

jb
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#10 John Brawley

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Posted 19 December 2008 - 11:44 PM

Without an in-camera meter (do these even exist on any pro MP cameras?) you'd actually need to meter through a polarizer oriented comparably, I think.


Not always so easy as most MP polarisers are linear (not circular) and they screw with most meters.

jb
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#11 Adrian Sierkowski

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Posted 19 December 2008 - 11:52 PM

I think my Tiffen is a Circular John or Jonathan can you focus me on that? I always just go 2 stops on it and it seems find for me. If anything 1/2 a stop difference is nothing in todays TK suites. Though, as it's a range of 1.5-2 stops I might start doing 1 2/3 from here on out.
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#12 John Brawley

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Posted 20 December 2008 - 12:06 AM

I think my Tiffen is a Circular John or Jonathan can you focus me on that? I always just go 2 stops on it and it seems find for me. If anything 1/2 a stop difference is nothing in todays TK suites. Though, as it's a range of 1.5-2 stops I might start doing 1 2/3 from here on out.



Im not sure about the circ's. The schneider's were more *polarised* than the tiffens hence the deeper filter factor. The test they used to have was to take two of their polarisers and rotate them together till you get total black. If you did the same with two tiffens you would always be able to still see through them, even at max polarisation. Hence schneider rightly claiming the polariser high ground and calling their polariser's *tru-pol*

I know tiffen were going to release a version that performed in a similar way to the schneider's but i don't think it's necessarily linked to weather they are circular or linear. I know schneider also have a 1 stop polariser as well.

jb
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#13 Jonathan Bowerbank

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Posted 20 December 2008 - 07:21 AM

I think my Tiffen is a Circular John or Jonathan can you focus me on that? I always just go 2 stops on it and it seems find for me. If anything 1/2 a stop difference is nothing in todays TK suites. Though, as it's a range of 1.5-2 stops I might start doing 1 2/3 from here on out.


I would go by Tiffen's own specifications. You can spot meter through it to find out, but it won't be exact, as Tiffen's tests take into count the spectral sensitivity effected by the pola filter, and not just flat exposure value.
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#14 David Mullen ASC

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Posted 20 December 2008 - 11:08 AM

I've found most Polas to be in the 1.5-stop range, which of course is a bit awkward to compensate on your meter by a half-stop unless you combine it with another half-stop loss filter like an 81EF... so I usually round up to 1 2/3 stops for a Pola.

I used to just use the Pola interchangeably with the ND.6, but I don't think it really is as dense as 2-stops...

Lately I've used a Pola less and less, mainly because now I seem to be noticing more problems with double-reflections from having a 4x5 ND filter or diffusion in front of the round Pola, and that gap between them, even if I tilt the filter. It's annoying, I've been burned a few times in dailies with ghost reflections. The only solution sometimes is to really tilt the filter, more than the tilt tray allows.

I wonder if anyone would make a Pola + ND.6 combo filter -- that would come in handy when shooting these newer digital cameras outside.
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#15 Paul Bruening

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Posted 20 December 2008 - 01:54 PM

Has anyone ever stacked polarizers? Would they cut more wavelengths or just more amount of light?
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#16 Hunter Hampton

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Posted 20 December 2008 - 03:08 PM

I have tried stacking linear polarizers before- it acts like a variable ND. I didn't notice more polarization?
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#17 Chris Keth

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Posted 20 December 2008 - 11:44 PM

You can stack them to do stuff like cut two different reflections or get really dark, surreal skies. It will just cut two different polarities of light.

I would recommend stacking the filters in the way they'll be used and metering through the pack to come up with a stop compensation. As you turn the filters in relation to each other you can actually get a setting that you can't even see through, I'm not sure if doubling the filter factor would be correct or not.

Edited by Chris Keth, 20 December 2008 - 11:45 PM.

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#18 Bernhard Zitz

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Posted 21 December 2008 - 08:56 AM

Has anyone ever stacked polarizers? Would they cut more wavelengths or just more amount of light?


http://www.jr-worldw...omparisons.html

click on polarizer on the lower left.

at the bottom of the page you'll find some interesting examples of combined pola-filters...

Edited by Bernhard Zitz, 21 December 2008 - 08:57 AM.

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#19 Paul Bruening

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Posted 21 December 2008 - 01:17 PM

Excellent link, Bernhard. Thanks.
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#20 Shehnad Jalal

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Posted 28 January 2009 - 09:08 AM

1-1/2 to 2 stops sounds right, but also, keep in mind that I believe it depends on the orientatio of the polarizer.

In other words, it is shot-specific, not a set factor.


Without an in-camera meter (do these even exist on any pro MP cameras?) you'd actually need to meter through a polarizer oriented comparably, I think.




even if the exposure compensation depends on the orientation of the polarizer, it will still be in between 1 1/2 to 2 stops right?
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