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  • Polarising Filter

    Mark Johnson

    My Sailing Page

    My Flickr

  • #2
    Re: Polarising Filter

    I've had a decent (Hoya) polarising filter for years, but have only used it for a couple of times. It's a faff to find the best position.

    Jim

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    • #3
      Steve

      on flickr

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      • #4
        Re: Polarising Filter

        I always found it easy to "find the best position" on my SLR. Not tried it on digital mirrorless and absolutely useless on a rangefinder.
        Steve

        on flickr

        Comment


        • #5
          Re: Polarising Filter


          I don't think the dehaze slider can recreate the exact effect - like adding soft grads in Lightroom it will allow you to do something approximating the same thing but not the thing itself.


          There's a great explanation of what you can - and can't achieve here.

          http://www.cambridgeincolour.com/tut...ng-filters.htmhttps://www.avforums.com/threads/cir...#post-25690250


          If you're interested but unconvinced there a loads on eBay for under a tenner.
          https://www.flickr.com/photos/amcuk/

          Comment


          • #6
            Re: Polarising Filter

            "it's actually two filters allowing one to rotate relative to the one that is fixed"

            I beg your pardon?

            That would be a variable ND filter, not a typical polariser. With a polariser you rotate the entire filter glass, not two separately as in a variable ND.

            Ian
            Founder and editor of:
            Olympus UK E-System User Group (http://e-group.uk.net)
            Four Thirds User (http://fourthirds-user.com)
            Digital Photography Now (http://dpnow.com)
            Olympus camera, lens, and accessory hire (http://e-group.uk.net/hire)

            Twitter: www.twitter.com/ian_burley
            Flickr: www.flickr.com/photos/dpnow/
            Pinterest: www.pinterest.com/ianburley/
            NEW: My personal BLOG ianburley.com
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            • #7
              Re: Polarising Filter

              A polariser can give photos an extra bit of punch in bright conditions - think of wearing polarising sunglasses; clouds suddenly have a lot more dimension and contrast, the sky looks more blue, some colours can be enhanced. It can also make the colour in a scene look less natural.

              Ian
              Founder and editor of:
              Olympus UK E-System User Group (http://e-group.uk.net)
              Four Thirds User (http://fourthirds-user.com)
              Digital Photography Now (http://dpnow.com)
              Olympus camera, lens, and accessory hire (http://e-group.uk.net/hire)

              Twitter: www.twitter.com/ian_burley
              Flickr: www.flickr.com/photos/dpnow/
              Pinterest: www.pinterest.com/ianburley/
              NEW: My personal BLOG ianburley.com
              sigpic

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              • #8
                Re: Polarising Filter

                Originally posted by Ian View Post
                "it's actually two filters allowing one to rotate relative to the one that is fixed"

                I beg your pardon?

                That would be a variable ND filter, not a typical polariser. With a polariser you rotate the entire filter glass, not two separately as in a variable ND.

                Ian
                A polariser needs two elements, one to allow the X plane and the second to attenuate the Y plane of the EM wave, or vice versa. By rotating one relative to the other the degree of attenuation can be modulated. Scatter causes incoherence in the plane.
                Steve

                on flickr

                Comment


                • #9
                  Re: Polarising Filter

                  Originally posted by Ricoh View Post
                  A polariser needs two elements, one to allow the X plane and the second to attenuate the Y plane of the EM wave, or vice versa. By rotating one relative to the other the degree of attenuation can be modulated. Scatter causes incoherence in the plane.
                  Come on your wording implied there are two physical filters that need to be rotated by the photographer independently of each other.

                  There are, indeed, two components to a circular polariser. The second does rotate the linearly polarised light transmitted by the first layer, but both components are fixed and do not move relative to each other.

                  Ian
                  Founder and editor of:
                  Olympus UK E-System User Group (http://e-group.uk.net)
                  Four Thirds User (http://fourthirds-user.com)
                  Digital Photography Now (http://dpnow.com)
                  Olympus camera, lens, and accessory hire (http://e-group.uk.net/hire)

                  Twitter: www.twitter.com/ian_burley
                  Flickr: www.flickr.com/photos/dpnow/
                  Pinterest: www.pinterest.com/ianburley/
                  NEW: My personal BLOG ianburley.com
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                  • #10
                    Re: Polarising Filter

                    One other thing to look out for when using a polarising filter is non-linear darkening - especially of dark blue skies, which can sometimes look odd and also mess up panorama stitching.

                    Ian
                    Founder and editor of:
                    Olympus UK E-System User Group (http://e-group.uk.net)
                    Four Thirds User (http://fourthirds-user.com)
                    Digital Photography Now (http://dpnow.com)
                    Olympus camera, lens, and accessory hire (http://e-group.uk.net/hire)

                    Twitter: www.twitter.com/ian_burley
                    Flickr: www.flickr.com/photos/dpnow/
                    Pinterest: www.pinterest.com/ianburley/
                    NEW: My personal BLOG ianburley.com
                    sigpic

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                    • #11
                      Re: Polarising Filter

                      Let me try again in simple terms. It’s one assembly and as I said above one glass surface is fixed, and the second is allowed to rotate. Light is a tricky son of a bitch, and all planes of orientation, on or off axis, are possible. The polariser helps discriminate the incoherent.

                      I’ll leave it there.
                      Steve

                      on flickr

                      Comment


                      • #12
                        Re: Polarising Filter

                        Not meaning to be unnecessarily bothersome, Steve, but that really doesn't sound right - the bit where you say "the second is allowed to rotate".

                        Polarisation is linear, regardless of whether the filter is an old fashioned linear type or the newer 'circular' type.

                        A circular type has linear polarising material on the scene-facing side. Bonded to that front layer is a second layer, on the side facing the lens, and this has the effect of turning the light wave as it passes through so in effect the wave spins around the axis of its travel and is no longer linearly polarised. But nothing in the filter glass sandwich physically moves independently, it's all one piece. The filter glass is usually (but not always) mounted so that it can be rotated in relation to the camera and lens. This is so that different angles of polarised light can be filtered according the the need of the photographer.

                        Ian
                        Founder and editor of:
                        Olympus UK E-System User Group (http://e-group.uk.net)
                        Four Thirds User (http://fourthirds-user.com)
                        Digital Photography Now (http://dpnow.com)
                        Olympus camera, lens, and accessory hire (http://e-group.uk.net/hire)

                        Twitter: www.twitter.com/ian_burley
                        Flickr: www.flickr.com/photos/dpnow/
                        Pinterest: www.pinterest.com/ianburley/
                        NEW: My personal BLOG ianburley.com
                        sigpic

                        Comment


                        • #13
                          Re: Polarising Filter

                          I think we're differing over semantics - the reason I'm being obstinate is that I feel there could otherwise be confusion.

                          Ian
                          Founder and editor of:
                          Olympus UK E-System User Group (http://e-group.uk.net)
                          Four Thirds User (http://fourthirds-user.com)
                          Digital Photography Now (http://dpnow.com)
                          Olympus camera, lens, and accessory hire (http://e-group.uk.net/hire)

                          Twitter: www.twitter.com/ian_burley
                          Flickr: www.flickr.com/photos/dpnow/
                          Pinterest: www.pinterest.com/ianburley/
                          NEW: My personal BLOG ianburley.com
                          sigpic

                          Comment


                          • #14
                            Re: Polarising Filter

                            Originally posted by Ian View Post
                            I think we're differing over semantics - the reason I'm being obstinate is that I feel there could otherwise be confusion.

                            Ian
                            One of my ex-colleagues would say "violently agreeing" - however my polarising filter is only one piece of glass and there's no revolving bits at all! (other than the whole filter)
                            I didn’t get where I am today....

                            Comment


                            • #15
                              Re: Polarising Filter


                              The 'same' cannot be achieved in post-processing but in many cases it's effects can be simulated.



                              One use of a PL filter is to reduce reflections from the surface of water, to help in seeing what's underneath. That's why anglers use polarising sunglasses. If you like photographing fish, there's no substitute.



                              Another use is to increase contrast in skies and that can usually be simulated fairly well, by increasing saturation of the sky area in post-processing.


                              There are other specialist applications, such as showing stress lines in plastics, for which there is no substitute.



                              I do have some PL filters but confess I rarely use them.


                              The 'double' types, with two components, are intended as variable neutral-density filters, which can occasionally be useful.
                              Mike
                              visit my Natural History Photos website:
                              http://www.botanicdesign.co.uk/Natur...story/home.htm

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