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"Sports" Polarizer

 
 
AustinMN
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      07-11-2007
On Jul 11, 8:09 am, Pat <(E-Mail Removed)> wrote:
> Geez. I thought this was a simple yes/no answer. I guess it is "no",
> that no one has seen one recently (say within the last decade or two).


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

Scroll down to the polarizer section, there it is. It took me 30
seconds on google using your terms. Instead of searching yourself,
you waited two days for someone else to do it for you, then complained
because they didn't.

Austin


 
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AustinMN
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      07-11-2007
On Jul 10, 7:44 pm, Joseph Miller <(E-Mail Removed)> wrote:
> I'm sorry, but your description doesn't seem to make sense. The light
> coming from normal scenes like those in sports is not circularly
> polarized, so a "circular polarizing filter" or filter designed to
> remove cilcularly polarized light wouldn't do anything.


Backwards. It would only admit circularly polarized light, blocking
all others.

Austin

 
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Pat
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      07-11-2007
On Jul 11, 1:54 pm, AustinMN <(E-Mail Removed)> wrote:
> On Jul 11, 8:09 am, Pat <(E-Mail Removed)> wrote:
>
> > Geez. I thought this was a simple yes/no answer. I guess it is "no",
> > that no one has seen one recently (say within the last decade or two).

>
> http://www.tiffen.com/filters.htm
>
> Scroll down to the polarizer section, there it is. It took me 30
> seconds on google using your terms. Instead of searching yourself,
> you waited two days for someone else to do it for you, then complained
> because they didn't.
>
> Austin


Ummm, maybe I'm missing something but I don't see it there. Which
filter are you referencing.

Searching myself? Heck I've been doing that for 20 years. You don't
think I've checked every website I can find? If it is still made,
it's made my some small specialty company or I might be able to find
one that is used.

 
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Joseph Miller
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      07-11-2007
AustinMN wrote:
> On Jul 10, 7:44 pm, Joseph Miller <(E-Mail Removed)> wrote:
>
>>I'm sorry, but your description doesn't seem to make sense. The light
>>coming from normal scenes like those in sports is not circularly
>>polarized, so a "circular polarizing filter" or filter designed to
>>remove cilcularly polarized light wouldn't do anything.

>
>
> Backwards. It would only admit circularly polarized light, blocking
> all others.
>
> Austin
>

Sorry for the loose terminology. I should have said "do anything you
want to do." If it only passed circularly poarized light, then in nearly
all scenes no light would get through, since virtually none of the light
would be circulalrly polarized.

Joe



 
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Joseph Miller
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      07-11-2007
Pat wrote:

> On Jul 11, 1:54 pm, AustinMN <(E-Mail Removed)> wrote:
>
>>On Jul 11, 8:09 am, Pat <(E-Mail Removed)> wrote:
>>
>>
>>>Geez. I thought this was a simple yes/no answer. I guess it is "no",
>>>that no one has seen one recently (say within the last decade or two).

>>
>>http://www.tiffen.com/filters.htm
>>
>>Scroll down to the polarizer section, there it is. It took me 30
>>seconds on google using your terms. Instead of searching yourself,
>>you waited two days for someone else to do it for you, then complained
>>because they didn't.
>>
>>Austin

>
>
> Ummm, maybe I'm missing something but I don't see it there. Which
> filter are you referencing.
>
> Searching myself? Heck I've been doing that for 20 years. You don't
> think I've checked every website I can find? If it is still made,
> it's made my some small specialty company or I might be able to find
> one that is used.
>


You are not missing anything. Those filters are the standard ones for
removing linearly polarized light. You can get two basic types: one just
is a simple linear polarizer, and the other first does the linear
polarization for the effect that you want and then converts that
linearally-polarized light into circularly-polarized light. The effect
on the scene being photographed is identical for both types, and the
rotation angles of the filters must be set for the desired effect. The
circular filter is used for cameras with internatl reflections that
could potentially interact with linerally polarized light and perhaps
throw off light metering. On straight-through cameras, like many P&S
ones, there is no need for the circular variety.

I still don't understand the principle behind that filter you used to have.

Joe
 
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Allen
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      07-11-2007
Pat wrote:
> On Jul 11, 1:54 pm, AustinMN <(E-Mail Removed)> wrote:
>> On Jul 11, 8:09 am, Pat <(E-Mail Removed)> wrote:
>>
>>> Geez. I thought this was a simple yes/no answer. I guess it is "no",
>>> that no one has seen one recently (say within the last decade or two).

>> http://www.tiffen.com/filters.htm
>>
>> Scroll down to the polarizer section, there it is. It took me 30
>> seconds on google using your terms. Instead of searching yourself,
>> you waited two days for someone else to do it for you, then complained
>> because they didn't.
>>
>> Austin

>
> Ummm, maybe I'm missing something but I don't see it there. Which
> filter are you referencing.
>
> Searching myself? Heck I've been doing that for 20 years. You don't
> think I've checked every website I can find? If it is still made,
> it's made my some small specialty company or I might be able to find
> one that is used.
>

The only Google references to the phrase "sports polarizer" are to this
thread. Looking for hits that contain both words, though not necessarily
in that order, brings up nothing relevant. Maybe Austin MN has a secret
version of Google.
Allen
 
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mark.thomas.7@gmail.com
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      07-12-2007
On Jul 12, 3:54 am, AustinMN <(E-Mail Removed)> wrote:
> On Jul 11, 8:09 am, Pat <(E-Mail Removed)> wrote:
>
> > Geez. I thought this was a simple yes/no answer. I guess it is "no",
> > that no one has seen one recently (say within the last decade or two).

>
> http://www.tiffen.com/filters.htm
>
> Scroll down to the polarizer section, there it is. It took me 30
> seconds on google using your terms. Instead of searching yourself,
> you waited two days for someone else to do it for you, then complained
> because they didn't.
>
> Austin


Austin, I think *you* need to read the op more carefully. It *isn't*
a 'circular' polariser (as we know it), that Pat has described.

 
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Rob Morley
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      07-12-2007
In article <(E-Mail Removed) .com>,
http://www.velocityreviews.com/forums/(E-Mail Removed) says...

> Austin, I think *you* need to read the op more carefully. It *isn't*
> a 'circular' polariser (as we know it), that Pat has described.
>
>

It seems to me that he /did/ describe a circular polariser, and then
added "It is NOT to be confused with the current circular
polarizer". So he's trying to find something that is functionally
identical to a circular polariser, yet is somehow different in a way
that he doesn't seem to be able to explain. Or am I missing something?
 
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BaumBadier
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      07-12-2007
On Thu, 12 Jul 2007 13:19:57 +0100, Rob Morley <(E-Mail Removed)> wrote:

>In article <(E-Mail Removed) .com>,
>(E-Mail Removed) says...
>
>> Austin, I think *you* need to read the op more carefully. It *isn't*
>> a 'circular' polariser (as we know it), that Pat has described.
>>
>>

>It seems to me that he /did/ describe a circular polariser, and then
>added "It is NOT to be confused with the current circular
>polarizer". So he's trying to find something that is functionally
>identical to a circular polariser, yet is somehow different in a way
>that he doesn't seem to be able to explain. Or am I missing something?


I recall, way back when, that some special-effects polarizers were made by
carefully cutting thin wedge shapes of the polarizing material and then
reassembling them into other configurations to see what they would do.
Eventually they became used as novelty weather-man's TV icons on their
weather-map boards during B&W TV days. Where the weather-map was illuminated
with a rotating polarized light and their sun and rain markers would "move" in
bands of brightness as the rotating polarized light hit them. The sun icon
slowly rotating in a star-burst pattern, or concentric waves from center to
edge, or the rain icon would slowly move in a downward slant in bands of light
and dark. Or the H and L pressure area markers would have all their little
triangles or semi-circles have waves of light and dark pass through them in the
direction that front was moving. (Or conversely a slowly rotating polarizer was
in front of the TV camera's lens instead of a studio-light, I know not which,
both would work, I only figured out how they were doing it at the time by
observation.)

If linear polarizing material was cut into narrow wedges with the plane of
polarization either perpendicular to or in line with the length of the wedge,
and then assembled of thin pie-slices so that (for all intents and purposes) the
polarization was in a concentric orientation, or in a ray-burst configuration,
then rotating that polarizer would not change its overall effect. If it was
constructed to have the polarization planes in a concentric orientation then the
part above the horizon would indeed darken the sky some. In total though, all
light entering the lens would cancel out the polarizing effect for anything in
the center. Because that light would pass through all parts of all the
polarizing planes. Only things nearer the edges of the FOV would be affected.

Perhaps this is how it was done and the type of device you are refering to? If
it is not available you could obtain some sheet polarizing material
(www.sciplus.com offers some at times) and manufacture one for yourself using
the above mentioned method. I'm not sure how good you could get with an x-acto
blade and carefully mounting the thin wedges between glass so that it appeared
nearly seamless, but if I was pressed to recreate that kind of thing I'd give it
a good try.

Do you recall at all if you could see some very fine lines radiating from the
center of that polarizer? If so, that would reveal how this was done.
 
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Scott Schuckert
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      07-12-2007
In article <(E-Mail Removed)> , Rob Morley
<(E-Mail Removed)> wrote:

> It seems to me that he /did/ describe a circular polariser, and then
> added "It is NOT to be confused with the current circular
> polarizer". So he's trying to find something that is functionally
> identical to a circular polariser, yet is somehow different in a way
> that he doesn't seem to be able to explain. Or am I missing something?


I'm confused too. I read it as he was looking for a polarizer that
darkened the sky but didn't need to be rotated to maintain the effect.
"Circular" in the sense that it blocked all angles of polarized light
at the same time. isn't that a neutral density filter? <GRIN>
 
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