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Re: Polarized Lenses

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  • Hank Ward
    Been wearing polarized sunglasses for years. Hike, climb and ski and has never been an issue.
    Message 1 of 11 , Jun 20, 2013
      Been wearing polarized sunglasses for years. Hike, climb and ski and has never been an issue.
    • john_friend
      Here s some info to help you understand how polarized sunglasses work. All light rays consist of a particular plane of polarization. You can think of a light
      Message 2 of 11 , Jun 20, 2013
        Here's some info to help you understand how polarized sunglasses work.

        All light rays consist of a particular plane of polarization. You can think of a light ray as having an orientation to it (up/down, left/right or any particular angle to it. Polarized sunglasses are made to block 100% of a particular plane of polarization.

        Light coming directly from the sun has random polarization. That means that every light ray (or photon to be technical) has it's own, completely random plane of polarization. If all the light stayed randomly polarized, then polarized sunglasses would block about 1/2 the light. All by itself, that would be fine. You'd have sunglasses that blocked half the light.

        Now, when light bounces off something and is reflected such as bouncing off light colored granite or particular bouncing off the surface of water, the random polarization becomes much more aligned all in one particular direction. The orientation of the polarized sunglasses is made to block all of this light that is reflected off a polished surface directly in front of you. In this case, polarized sunglasses will block way more than 50% of the light. They will block nearly all the reflected light and 50% of the non-reflected light. You WANT to block a lot of the reflected light because it's really just glare so this is good.

        In addition, some of the light coming through the atmosphere at certain angles also obtains a particular plane of polarization (no longer random). Your polarized sunglasses (when at just the right angle) will block a lot of that light too. You can often see this effect by rocking the orientation of your head from side to side when looking at the sky/horizon. At one particular orientation, the sky will be a lot bluer and there will be a lot more contrast with the clouds. This effect isn't quite as useful for sunglasses because the angle of maximum blockage isn't always just right for your sunglasses, but it is why using a rotating circular polarizer on your camera can really, really help the contrast of your pictures (I will be carrying one for my Fuji X-E1 camera on my JMT trip).

        So, the conclusion here is that polarized sunglasses are GREAT for backpacking. At worst, they block 50% of the light and at best they block much more than that including many glaring reflections. This is also why they are great for driving because polarized sunglasses can block 100% of the glare off the inside of the windshield when the dash is in bright sun.

        The other thing I'd suggest is to make sure whatever glasses you get have good bottom and side coverage. As there's a lot of reflected light off granite surfaces, you don't want a lot of light reaching your eyes from below or to the sides of the glasses. This won't be direct sunlight, but it can still be very bright. It often bounces off your skin, then off the inside of the glasses and then into your eyes reducing the contrast you can see and annoying your eyes. This is why many pro athletes (like baseball players) wear the eye black under their eyes because it prevents the reflection off their skin from reaching the inside of their sunglasses. Hikers probably don't need that if you have glasses that cover enough of your face and fit well enough (enough wrap around the sides and tight fit below the eyes).

        I'm absolutely wearing polarized sunglasses on my JMT trip and wouldn't consider wearing non-polarized.

        --John

        --- In johnmuirtrail@yahoogroups.com, "ravi_jmt2013" <ravi@...> wrote:
        >
        > I am getting ready to order prescription glacier glasses this week and have encountered some conflicting information regarding the pros and cons of polarization.
      • ravi_jmt2013
        Thanks for taking the time to write all of that up! I agree that polarization makes sense for backpacking. That warning from the vendor I m using regarding
        Message 3 of 11 , Jun 20, 2013
          Thanks for taking the time to write all of that up!

          I agree that polarization makes sense for backpacking. That warning from the vendor I'm using regarding impairment of accurate judgment of terrain just got me worried that I might be making a mistake.

          One of the main reasons I'm buying new sunglasses for the trip is precisely because of the issue of light coming in through the sides and top of my casual everyday sunglasses which are also polarized. These sunglasses work fine for backpacking in East Coast forests but I suspect they will be inadequate in the Sierra at elevation. I have tried overglasses and did not find them very comfortable so I'm going to have prescription lenses made. I'm probably going to go with the Jublo Colorado frames which seem to fit me the best of all the Jublo line at REI and they have removable side shields so I won't look totally ridiculous if I wear them in casual use on the street.


          --- In johnmuirtrail@yahoogroups.com, "john_friend" <yahoo@...> wrote:
          >
          > Here's some info to help you understand how polarized sunglasses work.
          >
          > All light rays consist of a particular plane of polarization. You can think of a light ray as having an orientation to it (up/down, left/right or any particular angle to it. Polarized sunglasses are made to block 100% of a particular plane of polarization.
          >
          > Light coming directly from the sun has random polarization. That means that every light ray (or photon to be technical) has it's own, completely random plane of polarization. If all the light stayed randomly polarized, then polarized sunglasses would block about 1/2 the light. All by itself, that would be fine. You'd have sunglasses that blocked half the light.
          >
          > Now, when light bounces off something and is reflected such as bouncing off light colored granite or particular bouncing off the surface of water, the random polarization becomes much more aligned all in one particular direction. The orientation of the polarized sunglasses is made to block all of this light that is reflected off a polished surface directly in front of you. In this case, polarized sunglasses will block way more than 50% of the light. They will block nearly all the reflected light and 50% of the non-reflected light. You WANT to block a lot of the reflected light because it's really just glare so this is good.
          >
          > In addition, some of the light coming through the atmosphere at certain angles also obtains a particular plane of polarization (no longer random). Your polarized sunglasses (when at just the right angle) will block a lot of that light too. You can often see this effect by rocking the orientation of your head from side to side when looking at the sky/horizon. At one particular orientation, the sky will be a lot bluer and there will be a lot more contrast with the clouds. This effect isn't quite as useful for sunglasses because the angle of maximum blockage isn't always just right for your sunglasses, but it is why using a rotating circular polarizer on your camera can really, really help the contrast of your pictures (I will be carrying one for my Fuji X-E1 camera on my JMT trip).
          >
          > So, the conclusion here is that polarized sunglasses are GREAT for backpacking. At worst, they block 50% of the light and at best they block much more than that including many glaring reflections. This is also why they are great for driving because polarized sunglasses can block 100% of the glare off the inside of the windshield when the dash is in bright sun.
          >
          > The other thing I'd suggest is to make sure whatever glasses you get have good bottom and side coverage. As there's a lot of reflected light off granite surfaces, you don't want a lot of light reaching your eyes from below or to the sides of the glasses. This won't be direct sunlight, but it can still be very bright. It often bounces off your skin, then off the inside of the glasses and then into your eyes reducing the contrast you can see and annoying your eyes. This is why many pro athletes (like baseball players) wear the eye black under their eyes because it prevents the reflection off their skin from reaching the inside of their sunglasses. Hikers probably don't need that if you have glasses that cover enough of your face and fit well enough (enough wrap around the sides and tight fit below the eyes).
          >
          > I'm absolutely wearing polarized sunglasses on my JMT trip and wouldn't consider wearing non-polarized.
          >
          > --John
          >
          > --- In johnmuirtrail@yahoogroups.com, "ravi_jmt2013" <ravi@> wrote:
          > >
          > > I am getting ready to order prescription glacier glasses this week and have encountered some conflicting information regarding the pros and cons of polarization.
          >
        • nedtibbits
          Polarized and UVA/B lenses (glass preferred) are what we have been using for the last 38 years for over-snow eye protection while snow-hiking during Mountain
          Message 4 of 11 , Jun 21, 2013
            Polarized and UVA/B lenses (glass preferred) are what we have been using for the last 38 years for over-snow eye protection while snow-hiking during Mountain Education’s year ‘round courses. Never had a problem judging what we had to deal with and appreciated the reduction of glare. I have been snow-blinded twice when I was not wearing good glasses and it wasn’t fun...
             
            Get the good stuff!
             
             
            Ned Tibbits, Director
            Mountain Education
            www.mountaineducation.org
             
            Sent: Thursday, June 20, 2013 6:16 AM
            Subject: [John Muir Trail] Polarized Lenses
             
             

            I am getting ready to order prescription glacier glasses this week and have encountered some conflicting information regarding the pros and cons of polarization. My impression has always been that polarization is generally beneficial due to the reduction of glare particularly near water. Obviously the JMT has lots of lakes and I thought that polarized lenses would be a benefit.

            However, one of the vendors I'm considering states the following regarding polarized lenses:

            " Polarizing is NOT recommended where accurate judgement of surfaces and terrain is critical (jumping crevasses, hanging from ropes). "

            When I called to ask for more details, the person I spoke to said that unless I planned to do rock climbing or similar activities, polarized lenses would be fine for backpacking.

            In general, I do not plan on doing any real "rock climbing" although I do non-technical rock scrambles on occasion. Also, if I do any early season backpacking over snow, that would involve a need to accurately judge surfaces. I'm thinking of places like the ice chute below Forrester Pass or glisadding down from passes. Things that I would encounter if I ever hike the PCT for example.

            So question for the group: Would you opt for polarized lenses? FWIW, I already have casual sunglasses that are polarized so I want the glacier glasses I'm buying to be optimized for high altitude hiking and occasional travel over snow and ice.

          • Ned Tibbits
            Julbo has been a sponsor of Mountain Education for the past three years and whether we are ski patrolling or ski-mountaineering in the high sierra they have
            Message 5 of 11 , Jun 21, 2013
              Julbo has been a sponsor of Mountain Education for the past three years and whether we are ski patrolling or ski-mountaineering in the high sierra they have served us well, design and function!
               
              Ned Tibbits, Director
              Mountain Education
              www.mountaineducation.org
               
              Sent: Thursday, June 20, 2013 2:21 PM
              Subject: [John Muir Trail] Re: Polarized Lenses
               
               

              Thanks for taking the time to write all of that up!

              I agree that polarization makes sense for backpacking. That warning from the vendor I'm using regarding impairment of accurate judgment of terrain just got me worried that I might be making a mistake.

              One of the main reasons I'm buying new sunglasses for the trip is precisely because of the issue of light coming in through the sides and top of my casual everyday sunglasses which are also polarized. These sunglasses work fine for backpacking in East Coast forests but I suspect they will be inadequate in the Sierra at elevation. I have tried overglasses and did not find them very comfortable so I'm going to have prescription lenses made. I'm probably going to go with the Jublo Colorado frames which seem to fit me the best of all the Jublo line at REI and they have removable side shields so I won't look totally ridiculous if I wear them in casual use on the street.

              --- In mailto:johnmuirtrail%40yahoogroups.com, "john_friend" <yahoo@...> wrote:

              >
              > Here's some info to help
              you understand how polarized sunglasses work.
              >
              > All light rays
              consist of a particular plane of polarization. You can think of a light ray as having an orientation to it (up/down, left/right or any particular angle to it. Polarized sunglasses are made to block 100% of a particular plane of polarization.
              >
              > Light coming directly from the sun has random
              polarization. That means that every light ray (or photon to be technical) has it's own, completely random plane of polarization. If all the light stayed randomly polarized, then polarized sunglasses would block about 1/2 the light. All by itself, that would be fine. You'd have sunglasses that blocked half the light.
              >
              > Now, when light bounces off something and is reflected
              such as bouncing off light colored granite or particular bouncing off the surface of water, the random polarization becomes much more aligned all in one particular direction. The orientation of the polarized sunglasses is made to block all of this light that is reflected off a polished surface directly in front of you. In this case, polarized sunglasses will block way more than 50% of the light. They will block nearly all the reflected light and 50% of the non-reflected light. You WANT to block a lot of the reflected light because it's really just glare so this is good.
              >
              > In addition, some of the
              light coming through the atmosphere at certain angles also obtains a particular plane of polarization (no longer random). Your polarized sunglasses (when at just the right angle) will block a lot of that light too. You can often see this effect by rocking the orientation of your head from side to side when looking at the sky/horizon. At one particular orientation, the sky will be a lot bluer and there will be a lot more contrast with the clouds. This effect isn't quite as useful for sunglasses because the angle of maximum blockage isn't always just right for your sunglasses, but it is why using a rotating circular polarizer on your camera can really, really help the contrast of your pictures (I will be carrying one for my Fuji X-E1 camera on my JMT trip).
              >
              > So, the
              conclusion here is that polarized sunglasses are GREAT for backpacking. At worst, they block 50% of the light and at best they block much more than that including many glaring reflections. This is also why they are great for driving because polarized sunglasses can block 100% of the glare off the inside of the windshield when the dash is in bright sun.
              >
              > The other thing I'd
              suggest is to make sure whatever glasses you get have good bottom and side coverage. As there's a lot of reflected light off granite surfaces, you don't want a lot of light reaching your eyes from below or to the sides of the glasses. This won't be direct sunlight, but it can still be very bright. It often bounces off your skin, then off the inside of the glasses and then into your eyes reducing the contrast you can see and annoying your eyes. This is why many pro athletes (like baseball players) wear the eye black under their eyes because it prevents the reflection off their skin from reaching the inside of their sunglasses. Hikers probably don't need that if you have glasses that cover enough of your face and fit well enough (enough wrap around the sides and tight fit below the eyes).
              >
              > I'm absolutely wearing polarized
              sunglasses on my JMT trip and wouldn't consider wearing non-polarized.
              >
              > --John
              >
              > --- In
              href="mailto:johnmuirtrail%40yahoogroups.com">mailto:johnmuirtrail%40yahoogroups.com, "ravi_jmt2013" <ravi@> wrote:
              > >
              > > I am getting ready
              to order prescription glacier glasses this week and have encountered some conflicting information regarding the pros and cons of polarization.
              >

            • Viraj Ward
              I second the opinion on the Julbo s. They provided superior side protection when I hiked on those long snow fields in 2011. Viraj Ward Sent from my iPhone
              Message 6 of 11 , Jun 21, 2013
                I second the opinion on the Julbo's. They provided superior side protection when I hiked on those long snow fields in 2011.
                Viraj Ward

                Sent from my iPhone

                On Jun 21, 2013, at 1:09 PM, "Ned Tibbits" <ned@...> wrote:

                 

                Julbo has been a sponsor of Mountain Education for the past three years and whether we are ski patrolling or ski-mountaineering in the high sierra they have served us well, design and function!
                 
                Ned Tibbits, Director
                Mountain Education
                www.mountaineducation.org
                 
                Sent: Thursday, June 20, 2013 2:21 PM
                Subject: [John Muir Trail] Re: Polarized Lenses
                 
                 

                Thanks for taking the time to write all of that up!

                I agree that polarization makes sense for backpacking. That warning from the vendor I'm using regarding impairment of accurate judgment of terrain just got me worried that I might be making a mistake.

                One of the main reasons I'm buying new sunglasses for the trip is precisely because of the issue of light coming in through the sides and top of my casual everyday sunglasses which are also polarized. These sunglasses work fine for backpacking in East Coast forests but I suspect they will be inadequate in the Sierra at elevation. I have tried overglasses and did not find them very comfortable so I'm going to have prescription lenses made. I'm probably going to go with the Jublo Colorado frames which seem to fit me the best of all the Jublo line at REI and they have removable side shields so I won't look totally ridiculous if I wear them in casual use on the street.

                --- In mailto:johnmuirtrail%40yahoogroups.com, "john_friend" <yahoo@...> wrote:
                >
                > Here's some info to help you understand how polarized sunglasses work.
                >
                > All light rays consist of a particular plane of polarization. You can think of a light ray as having an orientation to it (up/down, left/right or any particular angle to it. Polarized sunglasses are made to block 100% of a particular plane of polarization.
                >
                > Light coming directly from the sun has random polarization. That means that every light ray (or photon to be technical) has it's own, completely random plane of polarization. If all the light stayed randomly polarized, then polarized sunglasses would block about 1/2 the light. All by itself, that would be fine. You'd have sunglasses that blocked half the light.
                >
                > Now, when light bounces off something and is reflected such as bouncing off light colored granite or particular bouncing off the surface of water, the random polarization becomes much more aligned all in one particular direction. The orientation of the polarized sunglasses is made to block all of this light that is reflected off a polished surface directly in front of you. In this case, polarized sunglasses will block way more than 50% of the light. They will block nearly all the reflected light and 50% of the non-reflected light. You WANT to block a lot of the reflected light because it's really just glare so this is good.
                >
                > In addition, some of the light coming through the atmosphere at certain angles also obtains a particular plane of polarization (no longer random). Your polarized sunglasses (when at just the right angle) will block a lot of that light too. You can often see this effect by rocking the orientation of your head from side to side when looking at the sky/horizon. At one particular orientation, the sky will be a lot bluer and there will be a lot more contrast with the clouds. This effect isn't quite as useful for sunglasses because the angle of maximum blockage isn't always just right for your sunglasses, but it is why using a rotating circular polarizer on your camera can really, really help the contrast of your pictures (I will be carrying one for my Fuji X-E1 camera on my JMT trip).
                >
                > So, the conclusion here is that polarized sunglasses are GREAT for backpacking. At worst, they block 50% of the light and at best they block much more than that including many glaring reflections. This is also why they are great for driving because polarized sunglasses can block 100% of the glare off the inside of the windshield when the dash is in bright sun.
                >
                > The other thing I'd suggest is to make sure whatever glasses you get have good bottom and side coverage. As there's a lot of reflected light off granite surfaces, you don't want a lot of light reaching your eyes from below or to the sides of the glasses. This won't be direct sunlight, but it can still be very bright. It often bounces off your skin, then off the inside of the glasses and then into your eyes reducing the contrast you can see and annoying your eyes. This is why many pro athletes (like baseball players) wear the eye black under their eyes because it prevents the reflection off their skin from reaching the inside of their sunglasses. Hikers probably don't need that if you have glasses that cover enough of your face and fit well enough (enough wrap around the sides and tight fit below the eyes).
                >
                > I'm absolutely wearing polarized sunglasses on my JMT trip and wouldn't consider wearing non-polarized.
                >
                > --John
                >
                > --- In mailto:johnmuirtrail%40yahoogroups.com, "ravi_jmt2013" <ravi@> wrote:
                > >
                > > I am getting ready to order prescription glacier glasses this week and have encountered some conflicting information regarding the pros and cons of polarization.
                >

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