# polarizing filter



## ksmattfish (Jan 15, 2004)

I was digging through old pics, and I found this example of using a polarizing filter.  Nothing special about the subject or composition, but I think it is a good example of the effects of a pol filter.

I don't remember the kind of film.  These were shot on a tripod with a Norita 6x6 w/80mm f/2 lens.

Without polarizing filter







Same scene at the same time with a polarizing filter


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## pucci (Jan 16, 2004)

whoa sweet. i gotta get me a polarizing filter.


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## Bauhaus (Jan 30, 2004)

wow..   I'm gonna get one also.


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## cich (Jan 31, 2004)

They also can cut through glass/water reflections (circular polarizer at least...).

--cich

-------------------------------------
http://l0rdn1k0n.deviantart.com


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## ksmattfish (Jan 31, 2004)

Circular polarizers and linear polarizers pretty much do the same thing.  Circular polarizers were developed because linear polarizers mess with auto-focus.  So if your cam is AF, make sure you get a circ pol.


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## Harpper (Feb 5, 2004)

That's a huge difference! Thanks ksmattfish for posting the pictures. The lesson really hits home when we get to see the difference...



			
				cich said:
			
		

> They also can cut through glass/water reflections (circular polarizer at least...).


So using a polar filter is the best way to take pictures off water shimmering in the sunlight? The problem is I currently have a P&S camera but I guess I can hold the filter lens very close to the camera lens. I want to keep the shimmer affect but it doesn't come out to well. Although it might because I had the sun over head and in front of the camera.


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## ksmattfish (Feb 5, 2004)

You may find that you'll need a third hand.  A polarizing filter consists of two layers of glass that must be rotated properly, based on your relative position to the arc of the sun.  One hand to hold the camera, one hand to hold the filter, and one hand to turn the outer ring of the pol filter.  You could use a tripod to hold the camera.

The problem with using filters with point-n-shoots is that often they do not have TTL (through the lens) metering.  The meter is actually one of those other little openings, usually above the lens.  A pol filter blocks about 2 stops of light, so to get accurate metering you would need to make sure it was covering the meter, as well as the lens.

Sounds tricky to me.  Go out and buy a cheap used SLR.


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## soulfly (Feb 14, 2004)

I have a nice Quantaray circular polarizer, I got it for christmas and was wondering about the rotation part, how to use it properly...etc. I never used one before and it only has a couple of sentences on the back of the box, no instructions really. In case I have said it enough times already, its a canon T70, I do landscapes thru my Sakar 75-300mm macro/zoom, this is the lens the polarizer fits. any tips would be really appreciated.


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## photobug (Feb 14, 2004)

soulfly- basically you want to rotate the filter until the reflection is reduced. 

For reflections , you start with the sweet part of the filter pointing in the general direction of the sun or light source, then adjust from there.

For landscape type shots with lots of sky and the sun directly above you (or behind you), you'd start with the sweet spot pointing straight up and adjust (if needed) from there. For side or front lit scenes point the sweet spot at the light source and adjust as needed.

"Sweet spot" you ask? Most polarizers have text along the outside of the rim. That's usually where the filter effect is most prominent. Using the text to point toward the light source should provide the maximum effect of polarization (give or take a bit).

That's pretty much it. You have to play with your filter to determine exactly where the sweet spot for different situations is (they may be different). A small bit of colored tape on teh filter rim may be easier to use than the text, but that's personal preference.

Have fun!


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## ksmattfish (Feb 14, 2004)

Some filters have a mark at the "sweet spot".  The opposite side of the ring is also a "sweet spot".  On any sunny day the polarizing effect will be quite visible through your viewfinder; it will come and go as you rotate the outer ring of the filter.  On overcast days it can be tougher to see it, but it's there.  

The polarizing effect is strongest when the lens axis is perpendicular to the arc of travel of the sun, and the sweet spot is rotated until it points at the current location of the sun.

If the place on the horizon where the sun rises is 6:00, and the place where the sun sets is 12:00, then the strongest polarizing effect will occur when you are facing 9:00 and 3:00.  In this position it's also very easy to line up the sweet spot with the sun.

As your angle to the arc of the sun changes, you are turning away from 3:00 and 9:00 towards 6:00 and 12:00, the effect lessens.  You may notice a change in sky tone from one side of the image to the other (darker on the side closest to the sun's arc of travel).   

Facing 6:00 or 12:00 there may be hardly any polarizing effect at all.

Once you have the sweet spot lined up with the sun vertical movements (pointing the camera up or down, but still facing the same direction) don't seem to have much effect, but any horizontal turning will require the filter to be adjusted and the sweet spot re-aligned.


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## photobug (Feb 14, 2004)

Thanks Matt, for unconfusing my gibberish.


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## soulfly (Feb 14, 2004)

thanks very much. This site has officially taught me more than all the others i've been on put together.. again. thanks.


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## Kodan_Txips (Mar 3, 2005)

Just a point, but it may be an important one.

A linear polarising filter consists of only one sheet of glass, with some sort of "grid" manufactured within it.

I anticipate that the same will be true with a "circular" polarising filter - it is just that the grid is cirular rather than running in parallel lines.

Another point thus arises.  A circular piece of glass can contain parallel lines, and be a linear filter.  A square filter can have a concentric circular grid, and thus be a circular polariser.

Don't be fooled by the physical shape of the filter, it is the grid pattern that counts.


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## fadingaway1986 (Mar 3, 2005)

Oh you guys just completely confused me!

I just thought I put the filter on & it made the difference by having it there. I didn't know i had to turn it or anything!!!! arrrgh


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## fadingaway1986 (Mar 3, 2005)

Note: this also solves my problem of why I have so much trouble getting filters off! I've been turning the wrong ring!!!!!


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## 2Stupid2Duck (Mar 3, 2005)

LMAO.  I just spin it till I get a look I like.  You mean that little white line actually means summat???!!


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## siv (Mar 3, 2005)

damn, i gotta git me a polarizing filter once i rebuy a film camera (as i'm only digi now, not slr though, or i'd have one already....)


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## Xmetal (Mar 3, 2005)

*dumb question* Does a polarising filter on a camera work the same as a pair of polarised sunglasses?


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## Meysha (Mar 5, 2005)

Xmetal said:
			
		

> *dumb question* Does a polarising filter on a camera work the same as a pair of polarised sunglasses?



Not a dumb question. and Yep it's just like your sunglasses. Except you can't change the polarising in your glasses like you can in the filter because you can't twist the lenses in your glasses.

BUT... what you can do is tilt your head!!!
Try This: Go out side on a sunny day with your polarised sunnies and look at the sky, then slowly tilt your head and you'll notice the sky getting lighter! Just like what happens when you don't use a polarising filter.

Now I have a question for the filter buffs. What happens if you have a polarising filter on your camera and you take a photo of a window with polarising tint on it? Usually if you look through glasses the tinting on the window has funny patterns appear on it because of (i'm assuming) different levels/patterns of tinting - so you get dark and light areas, purple and blue and green areas. Has anyone taken a photo like this? Or does something strange happen? 
Because I've taken a lot of photos (with filter) on boats with tinted windows and I've never noticed the patterns.


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## ShutteredEye (Mar 6, 2005)

Meysha said:
			
		

> Not a dumb question. and Yep it's just like your sunglasses. Except you can't change the polarising in your glasses like you can in the filter because you can't twist the lenses in your glasses.
> 
> BUT... what you can do is tilt your head!!!
> Try This: Go out side on a sunny day with your polarised sunnies and look at the sky, then slowly tilt your head and you'll notice the sky getting lighter! Just like what happens when you don't use a polarising filter.
> ...



I know if you are using a linear polarizing filter that when the two polarized fields are perpendicular to each other, they will appear completely opaque.

I too got a polarizer for Christmas, haven't had a chance to use it yet. :meh:


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## MotorPsycho (Mar 6, 2005)

just out of curiosity, could someone post some links to manufactuers/sellers of quality polarizing filters?


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## Sergiozal (Mar 7, 2005)

Hey how much noise 

Polarizers are amazing and funny.

The linear seems to work better for get rid of reflexes such as water, windows, displays. The circular is good to get darker blue skies.\

I got both of them, but the amazing thing is when you stack one over the other, depending on which one of them is on top you can have:

1. A regulable neutral density filter (from ~20 - 100% darken)

2. A warm - cool filter (changing fron yellow to blue tones. Don't ask me why it happens, but is very interesting

*A nice article about polarizers:*

http://www.outdoorphotographer.com/content/pastissues/2001/july/polarizing.html


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## Sergiozal (Mar 7, 2005)

siv said:
			
		

> damn, i gotta git me a polarizing filter once i rebuy a film camera (as i'm only digi now, not slr though, or i'd have one already....)



Man, you can use it in your digi in the same way. I have a Canon A70 and I attach it on the lenses adapter. If you don't have an adapter, you can simply hold it in front of the lenses. No need of a third hand because you just choose the position you want it by looking through it, then put in front of your camera. 
Another thing: they are not expensive, and very helpfull


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## Sergiozal (Mar 7, 2005)

Other example:

No polarizer







With polarizer:


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## photo gal (Mar 8, 2005)

wow lots of great information here!!!Glad I read this thread, learned a lot!!!  Thanks  : )


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## PlasticSpanner (May 2, 2005)

Is it possible to apply a polarizing effect to scanned photos?


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## pursuer (May 3, 2005)

Here is an example of the polarizing effect on water.

without filter





with filter


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## JamesD (May 10, 2005)

PlasticSpanner said:
			
		

> Is it possible to apply a polarizing effect to scanned photos?



No, polarizers only work at the time the photo is taken. The light entering the lens may be polarized one way or the other, or even not at all, and the polarizer will block light which is polarized against its alignment. The film (or CCD, for digitals) does not record any information about the polarization of the light, only its intensity (and color, more or less). So, once the picture is made, all polarization is lost.

With that said, some of the effects may be reproduced manually in software. You can lighten or darken skys, tone down some reflections, increase saturation, etc, all of which are just some of the effects a polarizer can produce. This typically requires manually selecting and adjusting color/luminosity values.


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## Jeff Canes (May 10, 2005)

PlasticSpanner most of the examples show the effects that a polarizer filter has on colors, those effects can be done is PS manually or with custom action or dig-filter. 


The big effect that polarizers do are to cut down on glair or reflections off of water and glass & etc, this can not be done is PS. Pursuer examples show this some, the white water in his first one has more glair that in second.


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## Cuervo79 (May 11, 2005)

ksmattfish said:
			
		

> I was digging through old pics, and I found this example of using a polarizing filter. Nothing special about the subject or composition, but I think it is a good example of the effects of a pol filter.
> 
> I don't remember the kind of film. These were shot on a tripod with a Norita 6x6 w/80mm f/2 lens.
> 
> ...


FUNK what an amazing difference... you sure u only used a polarizing filter?


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## PlasticSpanner (May 11, 2005)

Jeff Canes said:
			
		

> PlasticSpanner most of the examples show the effects that a polarizer filter has on colors, those effects can be done is PS manually or with custom action or dig-filter. .



The colours and contrasts I can adjust manually & by eye so thats not really the problem!



			
				Jeff Canes said:
			
		

> The big effect that polarizers do are to cut down on glair or reflections off of water and glass & etc, this can not be done is PS. Pursuer examples show this some, the white water in his first one has more glair that in second.



This is the bit I was really interested in!  So there isn't a filter or plugin for PS to do this bit then?  I really can't imaging adjusting an origional by hand to get rid of all the light reflections and keep it consistant! Whoahh!

As for the effect! I looked at the green leaves on the tree to the left as well! Even the glistening on the leaves that makes them look fuzzy & out of focus a bit had been eliminated!

I have also noticed that when taking pictures of rally cars if I use the filter I can see the driver/co-driver behind the screen instead of a reflection of the sky! 

What a great filter! Thanks to all who posted in this thread & turned technical jargon into plain English!!! :thumbup:


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## M @ k o (May 13, 2005)

fadingaway1986 said:
			
		

> Oh you guys just completely confused me!
> 
> I just thought I put the filter on & it made the difference by having it there. I didn't know i had to turn it or anything!!!! arrrgh


 
LOL, me either.


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## M @ k o (May 13, 2005)

Sergiozal said:
			
		

> Other example:
> 
> No polarizer
> 
> ...


 
Did you use the same settings with the pol filter, like you did without it?


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## Soul Rebel (Feb 9, 2006)

Im a bit confused about polarizing filters. The camera I was given came with a polarizing filter that screws on. However, unlike some people are describing there is nothing to twist. What do I have?


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## doenoe (Feb 10, 2006)

I bought myself a polarizer 2 weeks ago, but i havent had the chance to use it yet. Cant wait to use it though, the difference between with and without the filter is just spectacular.


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