Circular polarizing filters

(7 posts)
  • Started 3 months ago by manappraisal
  • Latest reply from manappraisal
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    1. manappraisal
      Member

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       I am new to the world of filters. I just purchased a Hoya circluar polariziing filter and will be testing soon.

      My impression is that the filter is supposed to be adjustable via the free turning outer ring. However, when place to my eye and turned, nothing happens.  The outer ring turns freely, but no adjustment on the brightness occurs. Is this normal?  If so, then what does the outer ring do, if it does not vary the amount of light which passes through.  This experiment was done in bright sun light.

      Thanks.

       

      Jeff Deuitch

      Palmetto, Fl

       

       

      Posted 3 months ago # Login to Send PM
    2. robgrauert
      Member

      robgrauert

      Do you know what a polarizing filter does? It doesn't adjust brightness, it eliminates reflection when shooting through something like glass.

      Robert J. Grauert, Jr
      http://www.robgrauert.com
      Posted 3 months ago # Login to Send PM
    3. birdcat
      Moderator

      birdcat

      Try pointing the camera (with the filter on) at a reflection in a pane of glass (say at a 45 degree angle), then turn the ring and see what happens.  If you don't see a drastic difference (the reflection disappearing and what's behind the glass showing through), then you don't have a polarizing filter or you're doing something (like the mounting) drastically wrong.

      Perhaps you're wanting a neutral density filter?

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    4. manappraisal
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      No, definitely want a ploarizing filter. 

       Perhaps they work differently than the polarized glass we used to play with back in physics.  With these, light was only allowed to enter in a single plane.  If you put two pieces together in the same orientation, light was largely unaffected.  If you turned one of them 90 degrees, then one blocked out all the 'vertical" light and the other would block out all the "horizontal" light.  The nbet result was that no light passed through. I thought that perhaps a polarizing filter would work the same way. I did see a Youtube video where a guy had a circlar polarizing filter and demo'ed it with exactly the same results I am describing.  This is why I am a bit perplexed that the Hoya filter I purchased does not seem to do this.  It has the free truning ring in the front, but when looking through the filter by eye and turn the front ring, there is no perceptable difference.  It is definitely labeled as a polarizing filter. 

      Thanks.

       

      Jeff

       

      <p class="post">

      Try pointing the camera (with the filter on) at a reflection in a pane of glass (say at a 45 degree angle), then turn the ring and see what happens.  If you don't see a drastic difference (the reflection disappearing and what's behind the glass showing through), then you don't have a polarizing filter or you're doing something (like the mounting) drastically wrong.

      Perhaps you're wanting a neutral density filter?

      <p class="poststuff">Posted 1 hour ago # PM This User

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    5. birdcat
      Moderator

      birdcat

      You will get some light reduction but not to the extreme (like a stronger ND filter), however you should notice something when the filters are at opposing angles.  Hoya is a name brand so I don't think that's your problem.  If the filter is mounted correctly you should see something - I'm stumped.

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    6. D0n
      Member

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      did the thought occur to you that maybe the youtube clip you saw had used TWO polarizers? one on camera to exaggerate the effect, and the one you saw in the clip?

      the variable nd effect works best with two linear polarizers or one linear and one circular...

      to see the effects of a polarizer easily... point it up at blue sky 45 deg from the sun, then rotate it...

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    7. manappraisal
      Member

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      You know, I did not think about that.  It might be possible.  However, the person in the video seem to be describing the use of a single filter. I will go back and review.

       

      Thanks for the advice.  I am in a learning curve with respect to filters.

       

      Regards.

       

      Jeff Deuitch 

       

      did the thought occur to you that maybe the youtube clip you saw had used TWO polarizers? one on camera to exaggerate the effect, and the one you saw in the clip?

      the variable nd effect works best with two linear polarizers or one linear and one circular...

      to see the effects of a polarizer easily... point it up at blue sky 45 deg from the sun, then rotate it...

      Posted 3 months ago # Login to Send PM

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