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Re: [PanoToolsNG] spherical mirror

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  • Uri Cogan
    ... There exist several single-shot mirror systems using convex mirror optics. One example is at: http://www.3dvista.com/oneshot.htm The quality is never as
    Message 1 of 18 , May 2, 2010
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      On 5/2/10 12:12 PM, _kfj wrote:

      > After several years of amateur panoramas from ordinary cameras and
      > lenses I am considering buying a fisheye lens. But: it costs a lot of
      > money and/or has chromatic aberration (at least on the edges). So I
      > was wondering about spherical mirrors. They ought to be able to
      > produce images of almost the whole field of view and have no CA, be
      > lightweight and potentially even cheap! Has anyone out there used one
      > (or is there a ready-made spherical-mirror-lens around)? And where
      > could one find optical grade spherical mirrors if there are no
      > ready-made lenses? How does one go about getting the view and not an
      > image of oneself when using a spherical mirror? Maybe there are
      > alternatives which aren't spherical but some other convex, maybe
      > pointed, shape?
      >

      There exist several single-shot mirror systems using convex mirror
      optics. One example is at:

      http://www.3dvista.com/oneshot.htm

      The quality is never as good as that from a fisheye lens and they can
      only produce circular, but not spherical panoramas. The cost for the
      example system above is higher than some fairly high quality fisheye
      lenses (Samyang 8mm, etc.).

      CA in fisheye lenses is not much of a problem if you shoot RAW; it can
      be easily corrected in many RAW processors, and the distortion is taken
      care of by the stitching software.

      --

      Uri Cogan
      http://www.uricogan.com

      * "There is no green on their planet, they killed their Mother" *
      --AVATAR



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    • Erik Krause
      ... Wrong. A Samyang, a Zenitar or a Peleng are relatively cheap. The Samyang is very good: http://michel.thoby.free.fr/SAMYANG/Early%20test%20report.html ...
      Message 2 of 18 , May 2, 2010
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        Am 02.05.2010 21:12, schrieb _kfj:
        > But: it costs a lot of money and/or has chromatic aberration (at
        > least on the edges).

        Wrong. A Samyang, a Zenitar or a Peleng are relatively cheap. The
        Samyang is very good:
        http://michel.thoby.free.fr/SAMYANG/Early%20test%20report.html

        > So I was wondering about spherical mirrors. They
        > ought to be able to produce images of almost the whole field of view

        ... except what's behind the camera and what's behind the mirror. In
        practice the distortion near the mirrors edge is so high you won't get
        usable image data there. Hence the vertical FoV is limited to about 120°
        to 160°.

        > and have no CA,

        The mirrors not, but you still need a lens to shoot them, which still
        might have CA. Mirrors have other drawbacks: They don't reflect 100% of
        the ligth, any dust speck or finger print will be visible in the image,
        hence the dynamic range is limited. In short: nothing for serious work.

        > be lightweight and potentially even cheap! Has anyone
        > out there used one (or is there a ready-made spherical-mirror-lens
        > around)? And where could one find optical grade spherical mirrors if
        > there are no ready-made lenses?

        In addition to what Uri wrote: You can order single spherical lenses
        f.e. from http://www.linos.com and let them coat it. I asked some years
        agon and if I remember correctly the price was below 100 euros.

        > How does one go about getting the
        > view and not an image of oneself when using a spherical mirror? Maybe
        > there are alternatives which aren't spherical but some other convex,
        > maybe pointed, shape?

        Either you cut the camera out later or need to shoot from two different
        directions and stitch the result.

        Some years ago Uwe "hammernocker" Roßberg made a mirror for himself and
        shot some panoramas: http://www.hammernocker.de/panorama.php (choose a
        category on the left side).

        You'll probably agree that this is mainly for fun and not for serious
        panorama work...

        --
        Erik Krause
        http://www.erik-krause.de
      • Sacha Griffin
        How s your ballbearing? Someone recommended awhile ago chrome pinballs from some parts website. which I can say are not useable. Sacha From:
        Message 3 of 18 , May 2, 2010
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          How's your ballbearing? Someone recommended awhile ago chrome pinballs from
          some parts website. which I can say are not useable.





          Sacha



          From: PanoToolsNG@yahoogroups.com [mailto:PanoToolsNG@yahoogroups.com] On
          Behalf Of michael crane
          Sent: Sunday, May 02, 2010 3:41 PM
          To: PanoToolsNG@yahoogroups.com
          Subject: Re: [PanoToolsNG] spherical mirror



          I googled for you because I don't have a mirror I just have a shiny
          ballbearing





          [Non-text portions of this message have been removed]
        • Trausti Hraunfjord
          Used or new balls from some heavy duty bearings from earth moving machinery or balls from pin ball gaming machines or one shot mirror systems... I think the
          Message 4 of 18 , May 2, 2010
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            Used or new balls from some heavy duty bearings from earth moving machinery
            or balls from pin ball gaming machines or one shot mirror systems... I think
            the results will be about the same. Quite unusable for anything that is
            supposed to be decently looking.

            In today's technology, there is nothing that beats real cameras with real
            lenses. Maybe that will change in the future, but that future is not here
            yet.

            Trausti


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          • ptgroup
            In addition: you must go down to about F16 or even smaller to get the desired DOF. I tried several lenses (Nikon, Sigma at 50mm) and the complete mirror
            Message 5 of 18 , May 3, 2010
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              In addition:
              you must go down to about F16 or even smaller to get the desired DOF.
              I tried several lenses (Nikon, Sigma at 50mm) and the complete mirror
              (Panomaxx) was only sharp when shot @F16.
              This makes ist quite difficult when light is little low and ISO is an issue.
              Quality was not accaptable.
              But there was a mirror made in UK introduced in the Panoguide-forum some
              times ago.
              They got remarkable results - don´t have the thread at hand, sorry.



              Ciao
              Mike
              ----------------------------
              ----------------------------
              360° VR Fotografie:
              http://www.360de.de

              NEU: Abstrakte Fotografie unter:
              http://www.abstraktfoto.de
              -----------------------------
              Aktuelles vom Virtugrafen:
              http://virtugraf.wordpress.com
              -----Ursprüngliche Nachricht-----
              Von: PanoToolsNG@yahoogroups.com [mailto:PanoToolsNG@yahoogroups.com]Im
              Auftrag von _kfj
              Gesendet: Sonntag, 2. Mai 2010 21:13
              An: PanoToolsNG@yahoogroups.com
              Betreff: [PanoToolsNG] spherical mirror



              Hi everybody!
              After several years of amateur panoramas from ordinary cameras and lenses
              I am considering buying a fisheye lens. But: it costs a lot of money and/or
              has chromatic aberration (at least on the edges). So I was wondering about
              spherical mirrors. They ought to be able to produce images of almost the
              whole field of view and have no CA, be lightweight and potentially even
              cheap! Has anyone out there used one (or is there a ready-made
              spherical-mirror-lens around)? And where could one find optical grade
              spherical mirrors if there are no ready-made lenses? How does one go about
              getting the view and not an image of oneself when using a spherical mirror?
              Maybe there are alternatives which aren't spherical but some other convex,
              maybe pointed, shape?
              Thanks
              KFJ






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            • ptgroup
              Found the link: http://www.pano-pro.com/khxc/index.php Guess you don´t have to buy the whole system, just the mirror Ciao Mike 360° VR Fotografie:
              Message 6 of 18 , May 3, 2010
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                Found the link:
                http://www.pano-pro.com/khxc/index.php

                Guess you don´t have to buy the whole system, just the mirror

                Ciao
                Mike
                360° VR Fotografie:
                http://www.360de.de

                NEU: Abstrakte Fotografie unter:
                http://www.abstraktfoto.de
                -----------------------------
                Aktuelles vom Virtugrafen:
                http://virtugraf.wordpress.com
                -----Ursprüngliche Nachricht-----
                Von: PanoToolsNG@yahoogroups.com [mailto:PanoToolsNG@yahoogroups.com]Im
                Auftrag von _kfj
                Gesendet: Sonntag, 2. Mai 2010 21:13
                An: PanoToolsNG@yahoogroups.com
                Betreff: [PanoToolsNG] spherical mirror



                Hi everybody!
                After several years of amateur panoramas from ordinary cameras and lenses
                I am considering buying a fisheye lens. But: it costs a lot of money and/or
                has chromatic aberration (at least on the edges). So I was wondering about
                spherical mirrors. They ought to be able to produce images of almost the
                whole field of view and have no CA, be lightweight and potentially even
                cheap! Has anyone out there used one (or is there a ready-made
                spherical-mirror-lens around)? And where could one find optical grade
                spherical mirrors if there are no ready-made lenses? How does one go about
                getting the view and not an image of oneself when using a spherical mirror?
                Maybe there are alternatives which aren't spherical but some other convex,
                maybe pointed, shape?
                Thanks
                KFJ






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              • _kfj
                Thank you all for the good advice. Following the links on the Samyang 8mm I found out that it also sells as Walimex pro , at around 260€ via Amazon.de (I m
                Message 7 of 18 , May 3, 2010
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                  Thank you all for the good advice. Following the links on the Samyang 8mm I found out that it also sells as 'Walimex pro', at around 260€ via Amazon.de (I'm in Germany)
                  So that looks like a good option, never mind a bit of ghosting (might even be less problematic with an unshaved lens and 1.6 crop factor with my EOS 450D?!)
                  The replies to my post which yielded links for actual mirror lenses do tempt me to try one of those, too. Having everything in one single shot would make for a great quick reference, and the more detailed shots from other lenses might then be layered onto the more interesting parts of the image where one would be likely to zoom into it. Would be nice as a really small thing on a lightweight compact device with a GPS sensor... for years I have imagined things like a little knob to stick on top of your hat that take hi-res 360° images at movie rates so you could later virtually revisit where you've been!
                • Erik Krause
                  ... It will be more problematic since you need more shots and hence you ll have more overlap regions. ... That will be difficult. I guess you know about the no
                  Message 8 of 18 , May 3, 2010
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                    Am 03.05.2010 16:25, schrieb _kfj:

                    > So that looks like a good option, never mind a bit of ghosting (might
                    > even be less problematic with an unshaved lens and 1.6 crop factor
                    > with my EOS 450D?!)

                    It will be more problematic since you need more shots and hence you'll
                    have more overlap regions.

                    > The replies to my post which yielded links for actual mirror lenses
                    > do tempt me to try one of those, too. Having everything in one single
                    > shot would make for a great quick reference, and the more detailed
                    > shots from other lenses might then be layered onto the more
                    > interesting parts of the image where one would be likely to zoom into
                    > it.

                    That will be difficult. I guess you know about the no parallax point.
                    You'd need to place the lens in the NPP of the mirror...

                    --
                    Erik Krause
                    http://www.erik-krause.de
                  • Trausti Hraunfjord
                    I know of several people who have purchased single shot mirror systems. NONE of them uses or recommends the use of the systems. Most have tried to get some of
                    Message 9 of 18 , May 3, 2010
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                      I know of several people who have purchased single shot mirror systems.

                      NONE of them uses or recommends the use of the systems. Most have tried to
                      get some of their money back by selling the mirrors.

                      Don't forget that you are taking a picture of a mirror. The mirrors do have
                      imperfections in both the reflective material, and the glass... and some of
                      the systems do not even use glass... they use plastic. One scratch from a
                      grain of dust captured in a cleaning cloth... and it's good bye to that
                      mirror. A tiny little imperfection in the glass, will distort a big part of
                      the captured image. I have seen some horrible examples... and that is how
                      things are.

                      If you need to shoot cylindrical 360 video (in mediocre quality)... then go
                      ahead and get one of those systems.

                      .... you might just as well buy a SONY Bloggie.
                      http://www.thefind.com/search?query=sony+bloggie and thereby waste less
                      money.

                      Trausti


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                    • Rick Drew
                      Snip: I know of several people who have purchased single shot mirror systems. I sold mine on ebay a couple of years ago - the doughnut image takes up about 70%
                      Message 10 of 18 , May 3, 2010
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                        Snip: I know of several people who have purchased single shot mirror
                        systems.

                        I sold mine on ebay a couple of years ago - the doughnut image takes up
                        about 70% of the frame - or less. Plus you usually need to crop a little of
                        the top and bottom. So with a 10megapixel image, you're using about 7mp.
                        That's the max resolution. Then take into consideration problems inherent
                        with the mirror (everything from micro-scratches to dust) and the overall
                        soft focus. For down and dirty, poor quality, really fast shots, mirrors
                        are fine. For quality - forget it.



                        Rick Drew



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                      • Keith Martin
                        ... Yep. Although I m considering reversing things with the one I have and projecting a donut image up onto a mirror and out onto the walls of a room. With a
                        Message 11 of 18 , May 3, 2010
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                          >For down and dirty, poor quality, really fast shots, mirrors
                          >are fine. For quality - forget it.

                          Yep. Although I'm considering reversing things with the one I have
                          and projecting a donut image up onto a mirror and out onto the walls
                          of a room. With a powerful-enough projector it could get interesting.

                          I just have to figure out how to turn a properly-made equirect into a
                          (cylindrical) donut image.

                          k
                        • panovrx
                          ... Luc Courchesne does donut projection onto a mirror in his Panoscope 360 system for immersive 360 movies http://www.panoscope360.com/ I have tried the
                          Message 12 of 18 , May 3, 2010
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                            --- In PanoToolsNG@yahoogroups.com, Keith Martin <keith@...> wrote:


                            > Yep. Although I'm considering reversing things with the one I have
                            > and projecting a donut image up onto a mirror and out onto the walls
                            > of a room. With a powerful-enough projector it could get interesting.
                            >
                            > I just have to figure out how to turn a properly-made equirect into a
                            > (cylindrical) donut image.
                            >

                            Luc Courchesne does donut projection onto a mirror in his Panoscope 360
                            system for immersive 360 movies
                            http://www.panoscope360.com/

                            I have tried the screen you stand inside of model (with your head poking up thru a hole in the bottom of the screen) once -- and it was very effective. He used the same kind of mirror for capture and projection I think.

                            Now projection on large security mirrors is all the rage for budget dome projection setups too (portable planetaria etc).


                            Peter M
                          • panovrx
                            ... I checked my memory --- The one I tried The Visitor model actually uses a planar mirror to turn the projector beam 90 degrees onto a curved projection
                            Message 13 of 18 , May 3, 2010
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                              --- In PanoToolsNG@yahoogroups.com, "panovrx" <panovrx@...> wrote:
                              >
                              >
                              > --- In PanoToolsNG@yahoogroups.com, Keith Martin <keith@> wrote:
                              >
                              >
                              > > Yep. Although I'm considering reversing things with the one I have
                              > > and projecting a donut image up onto a mirror and out onto the walls
                              > > of a room. With a powerful-enough projector it could get interesting.
                              > >
                              > > I just have to figure out how to turn a properly-made equirect into a
                              > > (cylindrical) donut image.
                              > >
                              >
                              > Luc Courchesne does donut projection onto a mirror in his Panoscope 360
                              > system for immersive 360 movies
                              > http://www.panoscope360.com/
                              >
                              > I have tried the screen you stand inside of model (with your head poking up thru a hole in the bottom of the screen) once -- and it was very effective. He used the same kind of mirror for capture and projection I think.
                              >
                              > Now projection on large security mirrors is all the rage for budget dome projection setups too (portable planetaria etc).
                              >
                              >
                              > Peter M
                              >

                              I checked my memory ---
                              The one I tried "The Visitor" model actually uses a planar mirror to turn the projector beam 90 degrees onto a curved projection screen around the viewer. So he is not actually using a dome shaped mirror for projection -- though it is an interestingly direct way of showing mirror ball videos.
                            • L.D.I. Felipe B. González
                              Hi everyone! I used to have a 0-360 mirror. It was fun to use, but didn t render high quality panos. I even tried once to sell mirror panos, but the effort
                              Message 14 of 18 , May 3, 2010
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                                Hi everyone!

                                I used to have a 0-360 mirror. It was fun to use, but didn't render high
                                quality panos. I even tried once to sell mirror panos, but the effort
                                invested to obtain a decent looking pano was almost the same with the one
                                shot mirror than using a 8mm fisheye with 4 shots.
                                I sold it cheap to a student that was learning to program virtual tours. I
                                don't miss it.

                                Best regards from the subtropical regions of M�xico

                                2010/5/3 panovrx <panovrx@...>

                                >
                                >
                                >
                                >
                                > --- In PanoToolsNG@yahoogroups.com <PanoToolsNG%40yahoogroups.com>,
                                > "panovrx" <panovrx@...> wrote:
                                > >
                                > >
                                > > --- In PanoToolsNG@yahoogroups.com <PanoToolsNG%40yahoogroups.com>,
                                > Keith Martin <keith@> wrote:
                                > >
                                > >
                                > > > Yep. Although I'm considering reversing things with the one I have
                                > > > and projecting a donut image up onto a mirror and out onto the walls
                                > > > of a room. With a powerful-enough projector it could get interesting.
                                > > >
                                > > > I just have to figure out how to turn a properly-made equirect into a
                                > > > (cylindrical) donut image.
                                > > >
                                > >
                                > > Luc Courchesne does donut projection onto a mirror in his Panoscope 360
                                > > system for immersive 360 movies
                                > > http://www.panoscope360.com/
                                > >
                                > > I have tried the screen you stand inside of model (with your head poking
                                > up thru a hole in the bottom of the screen) once -- and it was very
                                > effective. He used the same kind of mirror for capture and projection I
                                > think.
                                > >
                                > > Now projection on large security mirrors is all the rage for budget dome
                                > projection setups too (portable planetaria etc).
                                > >
                                > >
                                > > Peter M
                                > >
                                >
                                > I checked my memory ---
                                > The one I tried "The Visitor" model actually uses a planar mirror to turn
                                > the projector beam 90 degrees onto a curved projection screen around the
                                > viewer. So he is not actually using a dome shaped mirror for projection --
                                > though it is an interestingly direct way of showing mirror ball videos.
                                >
                                >
                                >



                                --
                                L.D.I. Felipe B. Gonz�lez C.
                                felipe@...
                                1998-5246
                                www.fpk.com.mx
                                http://recorridosvirtualesmexico.blogspot.com/

                                Socio Director Maquetas Virtuales www.maquetasvirtuales.com
                                Socio Director Recorridos Virtuales www.recorridosvirtuales.com


                                [Non-text portions of this message have been removed]
                              • Bruce Hemming
                                I think that the OP was mainly referring to the use of reflective spheres - ie pin balls, garden gazers etc - rather than one shot mirror systems. Those
                                Message 15 of 18 , May 4, 2010
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                                  I think that the OP was mainly referring to the use of reflective
                                  spheres - ie pin balls, garden gazers etc - rather than one shot
                                  mirror systems. Those items were used to capture a fish eye scene
                                  for the preparation of light probes for 3D software using HDR - and I
                                  mean true HDR, not the debased meaning now in common usage. There
                                  were drawbacks of course as the scene was directional.

                                  Anyone who has Christian Bloch's definitive book The HDRI Handbook
                                  will be aware of this. It was a quick solution where the object was
                                  to capture the luminance range, not to produce a panoramic image. I
                                  think that most light probes are now captured using rotating camera
                                  panoramic techniques.

                                  Bruce Hemming
                                  Bruce Hemming Photography
                                  Tel: +44 (0)1580 200277
                                  Mobile: +44 (0)7974 918414
                                  e-Mail: bruce@...
                                  Skype: bhemmingphoto
                                  web :http://www.bhphoto.biz/





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                                • _kfj
                                  The no-parallax-poimt of the mirror. hmm. good point. If I understand this rightly, spherical mirrors do not hava a point of no parallax at all, so matching
                                  Message 16 of 18 , May 4, 2010
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                                    The no-parallax-poimt of the mirror. hmm. good point. If I understand this rightly, spherical mirrors do not hava a point of no parallax at all, so matching them with pictures shot through lenses would indeed be difficult - unless parallax is not an issue (like landscapes with nothing in the near foreground). Otherwise the problem should increase with the size of the mirror and the distance from it.
                                    BTW I had a look at your website and found your low-cost panorama head building instructions. I'm tying to emulate that with different materials and slight modifications, so far with very encouraging results! Thanks.
                                    KFJ

                                    --- In PanoToolsNG@yahoogroups.com, Erik Krause <erik.krause@...> wrote:

                                    > That will be difficult. I guess you know about the no parallax point.
                                    > You'd need to place the lens in the NPP of the mirror...
                                    >
                                    > --
                                    > Erik Krause
                                    > http://www.erik-krause.de
                                    >
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