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Old Dec 16, 2010, 6:24 PM   #1
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Default Polarizing Filter- How do you use it ?

I've never had or used, a polarizing filter, but friend of mine recently got one for his Pentax 55-300mm lens.

The camera store clerk attached this filter to the lens, but we don't know how to remove it from the end of the lens.

His camera is a Pentax K200D.

I know a polarizing filter is supposed to move around...but if you want to remove it....how do you do it ?

Also any tips for using a polarizing filter to it's best advantage ?

Are there conditions under which you should not use a polarizing filter and what would these be ?

Should a Polarizing filter be on the lens at all times, ie: also function as a protective filter ?

I have always used either a UV or a clear filter as protection for my lenses.

Thank you for any info.

Last edited by lesmore49; Dec 16, 2010 at 6:30 PM.
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Old Dec 16, 2010, 9:23 PM   #2
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See below for my 2 cents:


Quote:
Originally Posted by lesmore49 View Post
I've never had or used, a polarizing filter, but friend of mine recently got one for his Pentax 55-300mm lens.

The camera store clerk attached this filter to the lens, but we don't know how to remove it from the end of the lens.

The polarizer should have a rotating ring attached to a fixed ring. The fixed part screws into the threads on the end of the lens allowing you to rotate the movable part. To remove it, siimply grasp the fixed end and unscrew.

His camera is a Pentax K200D.

I know a polarizing filter is supposed to move around...but if you want to remove it....how do you do it ?

Also any tips for using a polarizing filter to it's best advantage ?

Are there conditions under which you should not use a polarizing filter and what would these be ?

Polarizers are typically used to eliminate reflections on glass or water etc. If you want to capture an image of a subject that is behind a glass that has a reflection, you can rotate the polarizer until the reflection is minized.

You can also use a polarizer to increase the saturation of colors. By eliminating reflections, you end up with bluer skies, greener grass and more intese yellows and reds. You can control the degree of saturation depending on how much rotation you apply. The results are clearly visible through the view finder.

For best results, your lens should point in a direction approximately 90 degrees from the source of light.

Finally, since a polarizer reduces the light trasmission by about 1 stop, it can also serve as a ND filter.

Should a Polarizing filter be on the lens at all times, ie: also function as a protective filter ?

It can be used as a protective filter, but at the expense of 1 stop exposure.

One thing I've noticed about using a polarizer with a wide angled lens is that parts of your image may have uneven saturation. A polarizer works best when the source of light is at about 90 degrees from the lens. Due to this, a wide angle lens will capture light from an angle much wider than 90 degrees and therefore could result in uneven distribution of saturation. I avoid using one on a wide angled lens.

I have always used either a UV or a clear filter as protection for my lenses.

Thank you for any info.
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Old Dec 16, 2010, 9:50 PM   #3
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Thank you Jelpee. Much appreciated.
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Old Dec 16, 2010, 10:08 PM   #4
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That 2 cents just about covered it. One other thing, though - if you use a bayonet lens hood, you can't use the polarizer, because you can't get your fingers in to turn it. You have to use a screw in lens hood, so make sure the filter has front threads. Some Pentax lens hoods have a pop-out window (the 55-300 has one) that lets you stick a finger in, but it is not very convenient or efficient to use for other than minor adjustments. For those who have a late model Tokina 80-400, there is an available bayonet lens hood with a thumbwheel that lets you rotate the polarizer.
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Old Dec 16, 2010, 10:49 PM   #5
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I've always thought that a polarizer acts sort-of like a mini-blind, it lets in light going one direction. That's why it's good for getting rid of reflections, it stops the light coming from the other direction. Rotating the filter changes the angle that it's allowing the light in, so the amount of effect changes. If you take two polarizers, one on top of the other, you can rotate them so that they won't let any light in (the second one blocking the direction of the light the first one lets in).

When I want to use one outside, I look for where the sun is in relation to my subject. I try to put the sun on my shoulder while facing my object, that puts the filter at 90 degrees (I'm better at remembering about remembering the shoulder than I am trying to figure out 90 degrees). Often people use it on bright, sunny days to darken the sky (a lot of the blue is caused by light bouncing around everywhere). It's more effective at higher altitudes for doing this.

Here's a couple of old pictures I took when I first got mine. It arrived on a very rainy day, so it gave me an opportunity to check out some of the effects.

Without the filter:



With filter:



Note the difference in the amount of reflection on the car's back window.

Another example, without polarizer:



With polarizer:



Notice the difference in color saturation and a lot less glare from the wet gray sky/atmosphere.

An example of what can happen using a polarizer with a wide angle. This picture is terrible in color - my first (and last!) experience with putting the polarizer on the 12-24. There's a significant difference in the blue color in the sky, ranging from mostly cyan on the right to dark navy blue on the left - it's really dreadful. However, by converting it to b&w you don't see the awful color transition so the picture works. The polarizer did do a good job of controlling the reflected light off of the snow, and b&w saved the picture. But even with the conversion you can see how much affect a polarizer can have on skies, depending on whether you are at right angles to the sun or not.


Last edited by mtngal; Dec 16, 2010 at 10:51 PM.
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Old Dec 17, 2010, 10:24 PM   #6
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Quote:
Originally Posted by penolta View Post
That 2 cents just about covered it. One other thing, though - if you use a bayonet lens hood, you can't use the polarizer, because you can't get your fingers in to turn it. You have to use a screw in lens hood, so make sure the filter has front threads. Some Pentax lens hoods have a pop-out window (the 55-300 has one) that lets you stick a finger in, but it is not very convenient or efficient to use for other than minor adjustments. For those who have a late model Tokina 80-400, there is an available bayonet lens hood with a thumbwheel that lets you rotate the polarizer.
My friend with the polarizer has it mounted on his 55-300 Pentax lens...but he's as clumsy as I am. I could see either one of us smudging the filter on a constant basis as we tried to move the polarizer, through the small gap in the lens hood.
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Old Dec 17, 2010, 10:30 PM   #7
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Quote:
Originally Posted by mtngal View Post
I've always thought that a polarizer acts sort-of like a mini-blind, it lets in light going one direction. That's why it's good for getting rid of reflections, it stops the light coming from the other direction. Rotating the filter changes the angle that it's allowing the light in, so the amount of effect changes. If you take two polarizers, one on top of the other, you can rotate them so that they won't let any light in (the second one blocking the direction of the light the first one lets in).

When I want to use one outside, I look for where the sun is in relation to my subject. I try to put the sun on my shoulder while facing my object, that puts the filter at 90 degrees (I'm better at remembering about remembering the shoulder than I am trying to figure out 90 degrees). Often people use it on bright, sunny days to darken the sky (a lot of the blue is caused by light bouncing around everywhere). It's more effective at higher altitudes for doing this.

Here's a couple of old pictures I took when I first got mine. It arrived on a very rainy day, so it gave me an opportunity to check out some of the effects.

Without the filter:



With filter:



Note the difference in the amount of reflection on the car's back window.

Another example, without polarizer:



With polarizer:



Notice the difference in color saturation and a lot less glare from the wet gray sky/atmosphere.

An example of what can happen using a polarizer with a wide angle. This picture is terrible in color - my first (and last!) experience with putting the polarizer on the 12-24. There's a significant difference in the blue color in the sky, ranging from mostly cyan on the right to dark navy blue on the left - it's really dreadful. However, by converting it to b&w you don't see the awful color transition so the picture works. The polarizer did do a good job of controlling the reflected light off of the snow, and b&w saved the picture. But even with the conversion you can see how much affect a polarizer can have on skies, depending on whether you are at right angles to the sun or not.

Thanks Mtngal. There do seem to be some concerns about using a polarized filter...as you have indicated.

I think I will keep my B+W clear filter on my 12-24mm....after reading about your adventures.
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Old Dec 17, 2010, 11:01 PM   #8
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Quote:
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if you use a bayonet lens hood, you can't use the polarizer, because you can't get your fingers in to turn it
I don't know if there's anything special about Pentax lenses, but I use a CPL filter with my Canon 24-105L zoom with the bayonet hood attached, with no problems. There's room to get two fingers in to rotate it. Quite impossible with my 100-400L though.
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Old Dec 18, 2010, 9:36 AM   #9
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Quote:
Originally Posted by peterbj7 View Post
I don't know if there's anything special about Pentax lenses, but I use a CPL filter with my Canon 24-105L zoom with the bayonet hood attached, with no problems. There's room to get two fingers in to rotate it. Quite impossible with my 100-400L though.

That sounds great that there is enough room in the Canon lens to get two fingers through. As was mentioned before, some of the Pentax lenses have a detachable cover on the hood that allows one to adjust the rotation of a CPL filter--pretty handy! I wish other manufacturers would do the same!
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Old Dec 18, 2010, 11:02 AM   #10
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I wish they had that cutout on the hood for the 100-400L.
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