Circular Polarizers, A Filter You Need

Circular Polarizers, A Filter You Need

Hi All,

I've written the first of a series of articles on the use of real camera
filters with digital photography. The first is on the circular polarizer
filter:
* w w w .dimagemaker . com /article.php?articleID=1063

Cheers,

Wayne
--
Wayne J. Cosshall
Publisher, The Digital ImageMaker, * w w w .dimagemaker . com /
Blog * w w w .digitalimagemakerworld . com /
Publisher, Experimental Digital Photography
* w w w .experimentaldigitalphotography . com
Personal art site * w w w .cosshall . com /

Re: Circular Polarizers, A Filter You Need


"Wayne J. Cosshall" <wayne@dimagemaker . com > wrote in message
news:46b98e0f$0$7152$afc38c87@news.optusnet . com .au...
> Hi All,
>
> I've written the first of a series of articles on the use of real camera
> filters with digital photography. The first is on the circular polarizer
> filter:
> * w w w .dimagemaker . com /article.php?articleID=1063

Great article.

Thanks.

Re: Circular Polarizers, A Filter You Need

On Aug 8, 5:33 am, "Wayne J. Cosshall" <wa...@dimagemaker . com > wrote:
> Hi All,
>
> I've written the first of a series of articles on the use of real camera
> filters with digital photography. The first is on the circular polarizer
> filter:
>
> Cheers,
>
> Wayne

I have one, rarely use it. Additionally, a 77mm multi-coated circular
polarizer to fit a great majority of my lenses, including my Mamiya
gear, costs a minimum of $150. It's not worth the money. And about
your examples, in the first series of thumbnail images, the one w/out
polarizer is clearly over exposed, the ones in which you indicate
reduced reflection from water and foliage are different, but not
necessarily better, and the darkened sky images look unnatural (and
again, you tend to overexpose, particularly in the ones with the dam
in the background). This is not to say the circular polarizer is not
without its uses, but to say it's a filter one "needs" is a stretch,
and a big one at that.

Finally, aren't you in essence spamming the photography groups in an
attempt to make money off our visits to your website, which are
replete with advertising? If you want to share info here, please do,
but your capitalist endeavors aren't welcome.

--
w w w .mattclara . com (not a single image there taken with a polarizer)

Re: Circular Polarizers, A Filter You Need

Matt Clara <mattclara@gmail . com > wrote in news:1186583221.191643.258650
@x40g2000prg.googlegroups . com :

> On Aug 8, 5:33 am, "Wayne J. Cosshall" <wa...@dimagemaker . com > wrote:
>> Hi All,
>>
<snip> on the circular polarizer </snip>

<snip> I have one, rarely use it. </snip>

If you're photographing with a wide-ish lens, you might like the effect of
the Moose Peterson filter. It's a warm polarizer. I don't use it a lot,
but it gives a nice (think Fuji Astia) warm, saturated look to the skies
and skins.

Re: Circular Polarizers, A Filter You Need

They were all exposed using auto exposure and none were autoleveled or
such in PS. Yes the first is over exposed to what I would want but I
left it in because I found it quite interesting that the camera itself
would get such different exposures of the scene with and without the filter.

For the article I used a quite wideangle lens to show the variation in
sky darkening with such a lens. With a narrower lens the sky effect can
be very strong with the right direction of camera relative to sun and
is, IMO, a very useful creative tool.

As to the rest of your comments, grow up. I publish an online magazine,
the same as the print photo mags I used to edit. I have every right to
put advertising on there if I want. If people don't want to they do not
have to click on anything except read the article. As it is I earn about
enough to cover my hosting costs. I assume you expect to get paid from
your job. Providing a site like DIMi, paying the costs and spending the
time organising the competitions, prizes, doing the reviews and
answering people's questions is a major effort. I do not see whiners
like you doing anything like this. Sure you'll get on a list and offer
opinions, it takes no real effort. When you put in the effort to do a
site like DIMi and keep doing it year on year then I might listen to
your crap.

Wayne J. Cosshall
Publisher, The Digital ImageMaker, * w w w .dimagemaker . com /
Blog * w w w .digitalimagemakerworld . com /
Publisher, Experimental Digital Photography
* w w w .experimentaldigitalphotography . com
Personal art site * w w w .cosshall . com /



Matt Clara wrote:
> On Aug 8, 5:33 am, "Wayne J. Cosshall" <wa...@dimagemaker . com > wrote:
>> Hi All,
>>
>> I've written the first of a series of articles on the use of real camera
>> filters with digital photography. The first is on the circular polarizer
>> filter:
>>
>> Cheers,
>>
>> Wayne
>
> I have one, rarely use it. Additionally, a 77mm multi-coated circular
> polarizer to fit a great majority of my lenses, including my Mamiya
> gear, costs a minimum of $150. It's not worth the money. And about
> your examples, in the first series of thumbnail images, the one w/out
> polarizer is clearly over exposed, the ones in which you indicate
> reduced reflection from water and foliage are different, but not
> necessarily better, and the darkened sky images look unnatural (and
> again, you tend to overexpose, particularly in the ones with the dam
> in the background). This is not to say the circular polarizer is not
> without its uses, but to say it's a filter one "needs" is a stretch,
> and a big one at that.
>
> Finally, aren't you in essence spamming the photography groups in an
> attempt to make money off our visits to your website, which are
> replete with advertising? If you want to share info here, please do,
> but your capitalist endeavors aren't welcome.
>
> --
> w w w .mattclara . com (not a single image there taken with a polarizer)
>

Re: Circular Polarizers, A Filter You Need

Wayne J. Cosshall wrote:
> Hi All,
>
> I've written the first of a series of articles on the use of real
> camera filters with digital photography. The first is on the circular
> polarizer filter:
> * w w w .dimagemaker . com /article.php?articleID=1063
>
> Cheers,
>
> Wayne

I have a circular and a linear polariser. I was told that I would be better
to use the circular polariser on my digital camera, as it would give better
results.
But I've used both the linear and the circular polarisers on my digital and
I honestly can't see any difference in the results when I compare the two.

Re: Circular Polarizers, A Filter You Need

"Fat Sam" <samandjanet@knox.orangehome.co.uk> wrote in message
news:G4WdnRPxh-gJRiTbRVnyugA@giganews . com ...
> Wayne J. Cosshall wrote:
>> Hi All,
>>
>> I've written the first of a series of articles on the use of real
>> camera filters with digital photography. The first is on the circular
>> polarizer filter:
>> * w w w .dimagemaker . com /article.php?articleID=1063
>>
>> Cheers,
>>
>> Wayne
>
> I have a circular and a linear polariser. I was told that I would be
> better to use the circular polariser on my digital camera, as it would
> give better results.
> But I've used both the linear and the circular polarisers on my digital
> and I honestly can't see any difference in the results when I compare the
> two.
>

The circular will tend to give slightly _poorer_ results, as it's designed
to let some polarized light through, as some camera's autofocus systems (and
ttl metering) depends upon it to get the job done.

--
w w w .mattclara . com

Re: Circular Polarizers, A Filter You Need

In article <NN2dnZ1nD_DyQyTbnZ2dnUVZ_smnnZ2d@comcast . com >,
"Matt Clara" <hey.wood.y@buzz.off> wrote:


> The circular will tend to give slightly _poorer_ results, as it's designed
> to let some polarized light through, as some camera's autofocus systems (and
> ttl metering) depends upon it to get the job done.
>
> --
> w w w .mattclara . com

No. They polarize exactly the same. All the quarter wave plate does is
allow some light to be processed properly by the AE or the AF, or both,
systems if your camera has a beam splitter in the optical path.

There are other factors that would make one type of polarizer more
effective then another. For instance a Kaesmann polarizer, linear or
circular, would be marginally more effective as the foil in a Kaesmann
is stretched tight in all directions and lies flatter then a simply
laminated polarizer. To keep the foil stretched tight the Kaesmann has
edge sealed glass rather then just laminated glass.

A properly hard coated polarizer with a modern MC that repels dust and
moisture while also passing up to 99.9% of the light hitting it to the
image plane (less what the polarizer eliminates of course) like the
Heliopan SH-PMC coated polarizers will be more effective then a coated,
uncoated or Kaesmann polarizer due to the coatings used. As well as the
quality of the foils used.

There are several grades of polarizers for optical use in photography.
Better polarizers use higher grades which are more color neutral and
have less effect on resolution then cheaper foils. The less expensive
polarizing filters may not be as effective due to the foil quality as
well as to the coatings and glass used.

--
To reply no_ HPMarketing Corp.

Re: Circular Polarizers, A Filter You Need

"Bob Salomon" <bob_salomon@mindspring . com > wrote in message
news:bob_salomon-2ED153.11324608082007@news.tellurian . net ...
> In article <NN2dnZ1nD_DyQyTbnZ2dnUVZ_smnnZ2d@comcast . com >,
> "Matt Clara" <hey.wood.y@buzz.off> wrote:
>
>
>> The circular will tend to give slightly _poorer_ results, as it's
>> designed
>> to let some polarized light through, as some camera's autofocus systems
>> (and
>> ttl metering) depends upon it to get the job done.
>>
>> --
>> w w w .mattclara . com
>
> No. They polarize exactly the same. All the quarter wave plate does is
> allow some light to be processed properly by the AE or the AF, or both,
> systems if your camera has a beam splitter in the optical path.
>
> There are other factors that would make one type of polarizer more
> effective then another. For instance a Kaesmann polarizer, linear or
> circular, would be marginally more effective as the foil in a Kaesmann
> is stretched tight in all directions and lies flatter then a simply
> laminated polarizer. To keep the foil stretched tight the Kaesmann has
> edge sealed glass rather then just laminated glass.
>
> A properly hard coated polarizer with a modern MC that repels dust and
> moisture while also passing up to 99.9% of the light hitting it to the
> image plane (less what the polarizer eliminates of course) like the
> Heliopan SH-PMC coated polarizers will be more effective then a coated,
> uncoated or Kaesmann polarizer due to the coatings used. As well as the
> quality of the foils used.
>
> There are several grades of polarizers for optical use in photography.
> Better polarizers use higher grades which are more color neutral and
> have less effect on resolution then cheaper foils. The less expensive
> polarizing filters may not be as effective due to the foil quality as
> well as to the coatings and glass used.
>


Damn, luminous landscape (and what I thought of as common knowledge) once
again let's us down:

"There are two types of polarizing filters available - linear or circular.
Linear polarizers are more effective and less expensive than circular ones.
But circular polarizers are needed with just about any camera that has a
through-the-lens metering system, or autofocus.

The reason for this is that both of these systems use semi-silvered mirrors
to siphon off some of the light coming though the lens. If that light is
linearly polarized it renders either the metering or the autofocus
ineffective. This means that you're going to have to buy circular polarizers
unless you're shooting with a pre-1970's camera, or a view camera."

--
w w w .mattclara . com

Re: Circular Polarizers, A Filter You Need

In article <CLOdnZxcQc8kdCTbnZ2dnUVZ_qGknZ2d@comcast . com >,
"Matt Clara" <hey.wood.y@buzz.off> wrote:

> The reason for this is that both of these systems use semi-silvered mirrors
> to siphon off some of the light coming though the lens. If that light is
> linearly polarized it renders either the metering or the autofocus
> ineffective. This means that you're going to have to buy circular polarizers
> unless you're shooting with a pre-1970's camera, or a view camera."

There is another reason that might effect some systems. And that is any
camera that has a polarized system in the viewfinder for display
readouts. If the camera has that type of display then as a linear
polarizer is rotated some display information may disappear and reappear
or be harder to read at some points of rotation then at others.

--
To reply no_ HPMarketing Corp.

Re: Circular Polarizers, A Filter You Need

"Matt Clara" <hey.wood.y@buzz.off> wrote:

>"Fat Sam" <samandjanet@knox.orangehome.co.uk> wrote in message
>news:G4WdnRPxh-gJRiTbRVnyugA@giganews . com ...
>> Wayne J. Cosshall wrote:
>>> Hi All,
>>>
>>> I've written the first of a series of articles on the use of real
>>> camera filters with digital photography. The first is on the circular
>>> polarizer filter:
>>> * w w w .dimagemaker . com /article.php?articleID=1063
>>>
>>> Cheers,
>>>
>>> Wayne
>>
>> I have a circular and a linear polariser. I was told that I would be
>> better to use the circular polariser on my digital camera, as it would
>> give better results.
>> But I've used both the linear and the circular polarisers on my digital
>> and I honestly can't see any difference in the results when I compare the
>> two.
>>
>
>The circular will tend to give slightly _poorer_ results, as it's designed
>to let some polarized light through, as some camera's autofocus systems (and
>ttl metering) depends upon it to get the job done.


Not so, Matt.

The circular polariser has two elements. The first is a linear
polariser, which has exactly the same blocking effect as any linear
polariser. The second element is a "quarter wave retarder" which
effectively unpolarises the polarised light, making it acceptable to
autofocus systems and some light metering systems, for example that of
the Nikon F3.

From the B+W web site:
"B+W pol-filters are made in various types and dimensions, both in the
form of linear as well as circular pol-filters. Basically, both
consist of a linearly polarizing film. With a circular polarizing
filter, an additional retardation film is added, which places the
linearly polarized light into rotation, thereby preventing erroneous
measurements in optical measurement systems; hence, for cameras with
internal devices for light meters (TTL) and/or autofocus, only
circular polarizing filters can be used! The same applies to digital
cameras and camcorders."

B+W are being cautious here, because only a very few manual focus SLRs
ever needed a circular polarising filter. Most TTL meters are
perfectly accurate when linear polarisers are used.

Re: Circular Polarizers, A Filter You Need- not so- linear vs. circular

Matt Clara wrote:


>
>
> The circular will tend to give slightly _poorer_ results, as it's designed
> to let some polarized light through, as some camera's autofocus systems (and
> ttl metering) depends upon it to get the job done.
>
> --
> w w w .mattclara . com
>
>

Both the circular and linear devices do exactly the same thing at the
first step- the light goes through a linear polaroid. That is where all
the action happens, all the filtering of the scene. For the simple
linear device, the light exits the filter essentially fully linearly
polarized and then enters the camera. Since reflections off surfaces can
polarize light, if there are any reflections inside the camera- say to
the viewfinder or to the light meter- there is the potential for
interactions, crossings, of this polarization with the incoming
polarization, which could affect the results in a negative way. If there
are no reflections in the camera, if the light goes straight through to
the focal plane and never is reflected, then linear polarized light
inside the camera should be irrelvant.

The circular device simply takes the linearly polarized light from the
first filter and converts it to circularly-polarized light by passing it
through a second filter, a quarter-wave retarder. If the filter is well
made, this second filter should result in no significant loss of light
or any other degradation of image quality. After exiting the filter,
circularly polarized light will pass though a camera just the same as
unpolarized light, in other words, just fine. The critical thing is that
it won't make any difference at what angle you set that first linear
polaroid.

There should be absolutely no difference in image quality between the
two filters if they are of comparable quality. For straight-through
cameras, there should be no performances differences. For cameras with
internal reflections, however, the circular polarizer will give more
reliable results, as the circularly polarized light it produces will be
immune to polarizing effects of the internal relections.

Since linear polarizers tend to be cheaper than circular ones, if you
have a straight through camera, you can probably save some money by
buying a linear device.

I hope this makes it a little clearer.

Joe

Re: Circular Polarizers, A Filter You Need- not so- linear vs. circular

On Aug 9, 12:17 am, Joseph Miller <mil...@ucolick.org> wrote:

> After exiting the filter,
> circularly polarized light will pass though a camera just the same as
> unpolarized light, in other words, just fine. The critical thing is that
> it won't make any difference at what angle you set that first linear
> polaroid.

Just to clarify this a bit, the angle of the polaroid filter makes no
difference as far as the passage through the camera is concerned (ie
it is not the case that, when it is set to some orientation, the AF
system, say, will fail). It does make a difference to the
transmittance, ie it does change the way the scene looks. I imagine
that this is what you meant, but what you wrote is a bit ambiguous.

Re: Circular Polarizers, A Filter You Need- not so- linear vs. circular

In article <1186606975.869385.189210@w3g2000hsg.googlegroups . com >,
acl <achilleaslazarides@yahoo.co.uk> wrote:

> On Aug 9, 12:17 am, Joseph Miller <mil...@ucolick.org> wrote:
>
> > After exiting the filter,
> > circularly polarized light will pass though a camera just the same as
> > unpolarized light, in other words, just fine. The critical thing is that
> > it won't make any difference at what angle you set that first linear
> > polaroid.
>
> Just to clarify this a bit, the angle of the polaroid filter makes no
> difference as far as the passage through the camera is concerned (ie
> it is not the case that, when it is set to some orientation, the AF
> system, say, will fail). It does make a difference to the
> transmittance, ie it does change the way the scene looks. I imagine
> that this is what you meant, but what you wrote is a bit ambiguous.

Yes, you put it more clearly. I meant as far as light going through the
camera itself is concerned, it makes no difference at which angle the
leading polaroid is set.

Joe

Re: Circular Polarizers, A Filter You Need

In article <G4WdnRPxh-gJRiTbRVnyugA@giganews . com >,
"Fat Sam" <samandjanet@knox.orangehome.co.uk> wrote:

> But I've used both the linear and the circular polarisers on my digital and
> I honestly can't see any difference in the results when I compare the two.

Nor should there be if they are the same quality. But under some
lighting conditions a linear polarizer will not let the AF or the AE or
both work properly if your camera has a beam splitter in the optical
system. If you have a camera without a beam splitter then you have no
reason to use a circular polarizer.

--
To reply no_ HPMarketing Corp.