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Polarization Filter?

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Category: Scopes
Forum Name: Rifle Scopes
Forum Description: Centerfire long gun scopes
URL: http://www.opticstalk.com/forum_posts.asp?TID=24717
Printed Date: March/28/2024 at 08:50
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Topic: Polarization Filter?
Posted By: Magnumdood
Subject: Polarization Filter?
Date Posted: August/13/2010 at 17:13
What does a Polarization Filter do?  Will it degrade the image on a riflescope, or will it enhance it?

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Replies:
Posted By: koshkin
Date Posted: August/13/2010 at 17:16
Polarization filter cuts out part of the light that is polarized in a particular way, hence the light that gets cut out differs depending on the orientation of the polarizer.  There are a few different types of polarization filters, so for an exact effect you have to be more specific.

As far as image quality, depending on the lighting conditions, location and filter type it may either degrade the image or enhance it.  There are not general answers for this question.

ILya


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Posted By: Magnumdood
Date Posted: August/13/2010 at 18:07
I purchased a Polarization filter from Hensoldt for my 6-24x72 scope just to protect the objective lens, as no one makes a flip-up that large.  I was just curious regarding what it did.  Several posters on Sniper's Hide opined that they didn't know why everyone didn't use one.

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America - Home of the Free

               Because of the Brave


Posted By: stickbow46
Date Posted: August/13/2010 at 18:14
You might want to look into getting a Skylight filter,I beleive it takes away less light than the polarizer.

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Pearls of Wisdom are Heard not Spoken


Posted By: koshkin
Date Posted: August/13/2010 at 18:15
Originally posted by Magnumdood Magnumdood wrote:

I purchased a Polarization filter from Hensoldt for my 6-24x72 scope just to protect the objective lens, as no one makes a flip-up that large.  I was just curious regarding what it did.  Several posters on Sniper's Hide opined that they didn't know why everyone didn't use one.

Using a polarization filter on your scope at all times is more than a little bit silly.  Depending on the conditions it diminishes the amount of light that passes through by ~50%.

It is likely that the polarizer you have is a circular polarizer and it is at its best when used in bright light when light loss is not critical.  If properly oriented, it will cut off the glare off of water or snow and make some of the colors pop.  In very low light, however, it can be a detriment.

ILya


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Posted By: pyro6999
Date Posted: August/13/2010 at 21:51
Originally posted by Magnumdood Magnumdood wrote:

What does a Polarization Filter do?  Will it degrade the image on a riflescope, or will it enhance it?

why are you taking your rifle fishing??Laugh


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Posted By: Magnumdood
Date Posted: August/13/2010 at 23:13
Originally posted by koshkin koshkin wrote:

Using a polarization filter on your scope at all times is more than a little bit silly.
O.K., but I have no intention of leaving the objective lens unprotected.  Any suggestions?

Originally posted by koshkin koshkin wrote:

It is likely that the polarizer you have is a circular polarizer...
ILya
It is.

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America - Home of the Free

               Because of the Brave


Posted By: tejas
Date Posted: August/14/2010 at 08:36
Good explanation from Koshkin. If you take two polorizers, and hold one in front of the other and turn them they will appear to go from solid black to clear. In some instances, they are great for camera lenses but used less these days due to photoshop software. Wouldnt use one on a scope unless i was shooting into the sun.


Posted By: Urimaginaryfrnd
Date Posted: August/14/2010 at 13:38
The main reason I can think of that a sniper might want a polarizing filter is to reduce the glare on glass if a target "bad guy" is the far side of a window or door.  When you think of a polarizing filter being useful that is like polarized sun glasses they cut reflection allowing you to look down into the water better. On traditional film cameras polarizing filters were used on the lens to create certain effects and since film has a fairly limited range of exposure latitude (what can be seen in bright areas and dark areas at the same time) you would put a polarizing filter on and the sky would look blue in the photo rather than white from being over exposed. Circular polarizers came into play when cameras became auto focus as the auto focus models would not focus if a traditional polarizer was in front of the lens.  The down side to a polarizing filter on a rifle scope it that also reduces the amount of light making it through the scope.    I use Leupold amber color Alumina Intensifying filters on two of my sniper scopes to protect the front lens element. I have always used UV/Haze filters on camera lenses (they look clear) to protect the front lens element.

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"Always do the right thing, just because it is the right thing to do".
Bobby Paul Doherty
Texas Ranger


Posted By: Magnumdood
Date Posted: August/14/2010 at 14:29
Do UV/Haze filters come in 72mm?

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America - Home of the Free

               Because of the Brave


Posted By: Urimaginaryfrnd
Date Posted: August/14/2010 at 14:54
Yes they do come in 72mm Hoya and several other manufacturers make filters for camera lenses and I'm pretty sure the thread pattern would be the same. http://www.hoyafilter.com/products/hoya/gf-01.html - http://www.hoyafilter.com/products/hoya/gf-01.html
Most camera stores or on line camera stores would carry them and very likely SWFA could special order them as they do business with Leica and Nikon.  About two years ago Leupold announced some filters for their scopes : http://swfa.com/Leupold-Alumina-RainCote-Kits-C977.aspx - http://swfa.com/Leupold-Alumina-RainCote-Kits-C977.aspx     http://swfa.com/Leupold-Alumina-Intensifier-Kits-C975.aspx - http://swfa.com/Leupold-Alumina-Intensifier-Kits-C975.aspx  in spite of a sincere effort on Leupold's part to advertise them I do not believe they have been very popular as most see no reason to add a filter. As an old photographer I really do see a reason to add a filter to protect the lens coatings on very expensive lenses. Scratch a filter throw it away and buy another but your expensive optic is un damaged.  I guess for guys who are buying two and three hundred dollar scopes its not an issue but I would think that guys buying thousand dollar plus scopes would be really concerned about that but I have not seen them educated in it to the point where they do it for the most part.

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"Always do the right thing, just because it is the right thing to do".
Bobby Paul Doherty
Texas Ranger


Posted By: Urimaginaryfrnd
Date Posted: August/14/2010 at 15:00
Go to a search engine and type in 72mm UV filter you will get lots of hits.
Also a possible is an 81a filter very light warming amber tone almost cant see it so light or 81b warming amber tone light but attractive to enhance skin tones and similar in tone but lighter than the Leupold alumina warm tone filter.


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"Always do the right thing, just because it is the right thing to do".
Bobby Paul Doherty
Texas Ranger


Posted By: tejas
Date Posted: August/14/2010 at 16:03
I will just stick to plain old flip up lens caps. Every piece of glass, no matter how good it is, that you add to any optical system has to degrade it, at least a little bit. Besides, while your screwing around with filters the opportunity to shoot might be gone.


Posted By: Magnumdood
Date Posted: August/14/2010 at 18:10
Originally posted by tejas tejas wrote:

I will just stick to plain old flip up lens caps. Every piece of glass, no matter how good it is, that you add to any optical system has to degrade it, at least a little bit. Besides, while your screwing around with filters the opportunity to shoot might be gone.
They don't make 72mm flip-ups.  I'm trying to buy some protection for my Hensoldt 6-24x72 objective. 


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America - Home of the Free

               Because of the Brave


Posted By: Magnumdood
Date Posted: August/14/2010 at 18:10
Originally posted by Urimaginaryfrnd Urimaginaryfrnd wrote:

Yes they do come in 72mm Hoya and several other manufacturers make filters for camera lenses and I'm pretty sure the thread pattern would be the same. http://www.hoyafilter.com/products/hoya/gf-01.html - http://www.hoyafilter.com/products/hoya/gf-01.html
Most camera stores or on line camera stores would carry them and very likely SWFA could special order them as they do business with Leica and Nikon.  About two years ago Leupold announced some filters for their scopes : http://swfa.com/Leupold-Alumina-RainCote-Kits-C977.aspx - http://swfa.com/Leupold-Alumina-RainCote-Kits-C977.aspx     http://swfa.com/Leupold-Alumina-Intensifier-Kits-C975.aspx - http://swfa.com/Leupold-Alumina-Intensifier-Kits-C975.aspx  in spite of a sincere effort on Leupold's part to advertise them I do not believe they have been very popular as most see no reason to add a filter. As an old photographer I really do see a reason to add a filter to protect the lens coatings on very expensive lenses. Scratch a filter throw it away and buy another but your expensive optic is un damaged.  I guess for guys who are buying two and three hundred dollar scopes its not an issue but I would think that guys buying thousand dollar plus scopes would be really concerned about that but I have not seen them educated in it to the point where they do it for the most part.
 
Thank you!


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America - Home of the Free

               Because of the Brave


Posted By: koshkin
Date Posted: August/14/2010 at 19:46
Originally posted by Magnumdood Magnumdood wrote:

Do UV/Haze filters come in 72mm?

Certainly.  One of my Zuiko lenses uses 72mm filters and I have a couple of UV blocking ones.  That would make a much better "stay on the rifle" piece than a polarizer.

Make sure the threads match.

ILya


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http://www.darklordofoptics.com - www.darklordofoptics.com
https://rumble.com/c/DLO - Rumble Video Channel


Posted By: tejas
Date Posted: August/14/2010 at 20:00
If you end up with photo filters look for B+w, or Helopan. Its been a while since I bought any but I think those are the premier brands with Schott glass. Hoya and Tiffen can be gotten in mid and low grades. B&H photo has everything  imaginable for camera lenses including some really cool neoprene camo covers.


Posted By: koshkin
Date Posted: August/14/2010 at 20:04
Originally posted by tejas tejas wrote:

If you end up with photo filters look for B+w, or Helopan. Its been a while since I bought any but I think those are the premier brands with Schott glass. Hoya and Tiffen can be gotten in mid and low grades. B&H photo has everything  imaginable for camera lenses including some really cool neoprene camo covers.

I only use B+W and higher end Hoyas. Both are equally good.  Lower end Hoyas are not great.

ILya


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http://www.darklordofoptics.com - www.darklordofoptics.com
https://rumble.com/c/DLO - Rumble Video Channel


Posted By: Magnumdood
Date Posted: August/14/2010 at 23:00
Ilya,
 
I ordered the B+W 72mm Clear Lens Protection Filter.


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America - Home of the Free

               Because of the Brave


Posted By: koshkin
Date Posted: August/15/2010 at 00:14
Originally posted by Magnumdood Magnumdood wrote:

Ilya,
 
I ordered the B+W 72mm Clear Lens Protection Filter.

THat should work fine for protecting the fron element of your scope.

ILya


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http://www.darklordofoptics.com - www.darklordofoptics.com
https://rumble.com/c/DLO - Rumble Video Channel


Posted By: Magnumdood
Date Posted: August/21/2010 at 19:42
Ilya,
 
The B+W arrived and it doesn't come close to matching the threads of the Hensoldt.  Do you think a Hoya would match?


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America - Home of the Free

               Because of the Brave


Posted By: koshkin
Date Posted: August/22/2010 at 00:36
Originally posted by Magnumdood Magnumdood wrote:

Ilya,
 
The B+W arrived and it doesn't come close to matching the threads of the Hensoldt.  Do you think a Hoya would match?

I suspect that B+W and Hoya have the same threads, so probably not.  In principel, you could have a converter made, but it will take some custom machining.

ILya


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http://www.darklordofoptics.com - www.darklordofoptics.com
https://rumble.com/c/DLO - Rumble Video Channel


Posted By: Magnumdood
Date Posted: August/22/2010 at 11:34

Who would do custom machining to make the converter?



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America - Home of the Free

               Because of the Brave


Posted By: koshkin
Date Posted: August/22/2010 at 12:41
Originally posted by Magnumdood Magnumdood wrote:

Who would do custom machining to make the converter?


Honestly, I am not sure.  I have never run into this problem before.

ILya


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http://www.darklordofoptics.com - www.darklordofoptics.com
https://rumble.com/c/DLO - Rumble Video Channel


Posted By: Magnumdood
Date Posted: August/22/2010 at 16:45

I think it would wind up costing more than it's worth...and when you're talking about protecting the optics on a Hensoldt, you know as well as I do, that's a pretty penny.  I talked with Nathan at HUDisCO, and he felt my best alternative was an infrared filter.  $450.00 for the infrared filter...I just don't know.



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America - Home of the Free

               Because of the Brave



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