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Linear vs. Circular Polarizer ?

 
 
Dave
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      12-09-2003
Doesn't a linear polarizer have greater usefulness than a circular one
if the camera itself (internal beamsplitter) is not an issue? Has
anyone compiled a list of cameras that really need to use only
circular polarizers?
 
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Bob Salomon
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      12-09-2003
In article <(E-Mail Removed) >,
http://www.velocityreviews.com/forums/(E-Mail Removed) (Dave) wrote:

> Doesn't a linear polarizer have greater usefulness than a circular one
> if the camera itself (internal beamsplitter) is not an issue? Has
> anyone compiled a list of cameras that really need to use only
> circular polarizers?


Any camera can use a circular polarizer. Any camera using a beam
splitter in the light path for metering, focus or the viewfinder display
should not use a linear polarizer.

So if you want one polarizer to work under all lighting conditions with
any type of camera or lens it is the circular polarizer.

Since both types use the same polarizing foil your premise is incorrect.
The difference between them is the addition of the quarter wave plate
behind the foil in the circular. Otherwise they are identical.

--
To reply no_ HPMarketing Corp.
 
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Jim Townsend
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      12-09-2003
Dave wrote:

> Doesn't a linear polarizer have greater usefulness than a circular one
> if the camera itself (internal beamsplitter) is not an issue? Has
> anyone compiled a list of cameras that really need to use only
> circular polarizers?


There is no difference in the effect produced by linear and circular
polarizers.. For all intents and purposes, they both do the same thing.

I know of no list of recommended polarizers by camera.




 
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Dave
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      12-09-2003
Bob Salomon <(E-Mail Removed)> wrote in message news:<(E-Mail Removed)>...
> In article <(E-Mail Removed) >,
> (E-Mail Removed) (Dave) wrote:
>
> > Doesn't a linear polarizer have greater usefulness than a circular one
> > if the camera itself (internal beamsplitter) is not an issue? Has
> > anyone compiled a list of cameras that really need to use only
> > circular polarizers?

>
> Any camera can use a circular polarizer. Any camera using a beam
> splitter in the light path for metering, focus or the viewfinder display
> should not use a linear polarizer.
>
> So if you want one polarizer to work under all lighting conditions with
> any type of camera or lens it is the circular polarizer.
>
> Since both types use the same polarizing foil your premise is incorrect.
> The difference between them is the addition of the quarter wave plate
> behind the foil in the circular. Otherwise they are identical.


Oh, so you're saying they are both functionally identical as far as a
user can see? They both accept incident light according to its linear
polarization and are manually rotated by the user for maximum
effectiveness?
 
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Michael Meissner
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      12-09-2003
Jim Townsend <(E-Mail Removed)> writes:

> Dave wrote:
>
> > Doesn't a linear polarizer have greater usefulness than a circular one
> > if the camera itself (internal beamsplitter) is not an issue? Has
> > anyone compiled a list of cameras that really need to use only
> > circular polarizers?

>
> There is no difference in the effect produced by linear and circular
> polarizers.. For all intents and purposes, they both do the same thing.


One place that I've read that it makes a difference is if you make a variable
polarizer by stacking two polarizers, the one closest to the camera should be a
linear polarizer. Of course you would need to have a really bright day to use
two polarizers.

Another difference is filter manufacturers only make circular polarizers
multi-coated (if you are willing to pay the price for a MC polarizer).

--
Michael Meissner
email: (E-Mail Removed)
http://www.the-meissners.org
 
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IK
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      12-09-2003
In article <(E-Mail Removed)-meissners.org>, mrmnews@the-
meissners.org says...

> Another difference is filter manufacturers only make circular polarizers
> multi-coated (if you are willing to pay the price for a MC polarizer).


B+W makes multicoated (MRC) LP. Not sure if other brands do.
 
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Tony Spadaro
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      12-09-2003
The liniear has one major advantage -- price.

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home of The Camera-ist's Manifesto
The Improved Links Pages are at
http://www.chapelhillnoir.com/links/mlinks00.html
A sample chapter from my novel "Haight-Ashbury" is at
http://www.chapelhillnoir.com/writ/hait/hatitl.html
"Dave" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> Doesn't a linear polarizer have greater usefulness than a circular one
> if the camera itself (internal beamsplitter) is not an issue? Has
> anyone compiled a list of cameras that really need to use only
> circular polarizers?



 
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Tony Spadaro
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      12-09-2003
If you stack a linear pol next to the camera would you not destroy your
ability to use the meter? Not that I've found the meter overly usefull with
2 circular pols --- When I've down this with two circular pols (which is
what I own) and a reversing ring so the back sides (with the de polirizing
modifier on both the front and back of the combination -- I have to open up
4 stops from the metered reading and bracket UP from there -- usually to
about 8 stops over. Putting them so they were both facing forward I go no
light at all into the camera.

--
http://www.chapelhillnoir.com
home of The Camera-ist's Manifesto
The Improved Links Pages are at
http://www.chapelhillnoir.com/links/mlinks00.html
A sample chapter from my novel "Haight-Ashbury" is at
http://www.chapelhillnoir.com/writ/hait/hatitl.html
"Michael Meissner" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)-meissners.org...
> Jim Townsend <(E-Mail Removed)> writes:
>
> > Dave wrote:
> >
> > > Doesn't a linear polarizer have greater usefulness than a circular one
> > > if the camera itself (internal beamsplitter) is not an issue? Has
> > > anyone compiled a list of cameras that really need to use only
> > > circular polarizers?

> >
> > There is no difference in the effect produced by linear and circular
> > polarizers.. For all intents and purposes, they both do the same thing.

>
> One place that I've read that it makes a difference is if you make a

variable
> polarizer by stacking two polarizers, the one closest to the camera should

be a
> linear polarizer. Of course you would need to have a really bright day to

use
> two polarizers.
>
> Another difference is filter manufacturers only make circular polarizers
> multi-coated (if you are willing to pay the price for a MC polarizer).
>
> --
> Michael Meissner
> email: (E-Mail Removed)
> http://www.the-meissners.org



 
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Dave
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      12-10-2003
"Tony Spadaro" <(E-Mail Removed)> wrote in message news:<PFsBb.109425$(E-Mail Removed) .com>...
>
> The linear has one major advantage -- price.
>


So I can perhaps get a linear multi-coated for the price of a coated
circular? Now which online reviews will tell me whether a C-750 needs
a circular?
 
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Dave Martindale
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      12-10-2003
(E-Mail Removed) (Dave) writes:

>Oh, so you're saying they are both functionally identical as far as a
>user can see? They both accept incident light according to its linear
>polarization and are manually rotated by the user for maximum
>effectiveness?


That's right. Both have a linear polarizing element in front.

The difference is that the linear polarizing filter has nothing else,
and so the light exits into the camera still linearly polarized. The
circular polarizer has a quarter-wave plate mounted behind the
polarizing element, oriented 45 degrees from the polarizer, which
converts linearly polarized light into circularly polarized light.
And circularly polarized light, for most purposes, behaves like randomly
polarized light - which is what any beamsplitters are expecting.

Now, I recently speculated that the anti-aliasing filters in most
digital cameras are designed to work with circular or randomly polarized
light, so it might be best to use a circular polarizer even if there
isn't a beamsplitter. But I don't have any test results to confirm
this.

Dave
 
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