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RE: [PanoToolsNG] Re: Sigma 10-20 any experiance?

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  • Sacha Griffin
    That was a bit confusing wasn t it? The canon ties or is better in all respects than the sigma. I love my canon lens. I take more photos with it than all my
    Message 1 of 17 , Dec 2, 2006
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      That was a bit confusing wasn't it?

      The canon ties or is better in all respects than the sigma.
      I love my canon lens. I take more photos with it than all my other lenses
      combined... And if you manual focus and have a good enough eye to do that,
      the sharpness you can get is incredible. Additionally, when focusing the
      rear element moves, not the front. I "believe" this is the cause for having
      the same nodal point at 22mm as it does at 10mm.

      Sacha Griffin
      Southern Digital Solutions LLC
      www.southern-digital.com
      www.seeit360.net
      www.ezphotosafe.com
      404-551-4275
      404-731-7798

      -----Original Message-----
      From: Tim Hatch [mailto:tim@...]
      Sent: Saturday, December 02, 2006 1:38 PM
      To: PanoToolsNG@yahoogroups.com
      Subject: [PanoToolsNG] Re: Sigma 10-20 any experiance?

      > As for the sigma 10-20 I think most agree the canon is sharper, has
      > more
      > contrast, & less distortion than the canon.. Plus it's slower.

      Which one is sharper and has less distortion?

      Tim


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      Yahoo! Groups Links
    • yertletertle
      ... Is this really true anymore? I shoot partial 360 s at 18mm on a 1.5 crop DSLR, and at full resolution (14kpix wide), I can obtain quite reasonable file
      Message 2 of 17 , Dec 3, 2006
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        --- In PanoToolsNG@yahoogroups.com, "Sacha Griffin" <sachagriffin@...> wrote:

        > For sphericals a 10mm rectilinear is overkill because it can't not be
        > displayed at full resolution conveniently over the net.
        > This is also true with the 10.5, however the 10.5 is more convenient to
        > shoot with (less shots, less moving subject issues).

        Is this really true anymore? I shoot partial 360's at 18mm on a 1.5 crop DSLR, and at full
        resolution (14kpix wide), I can obtain quite reasonable file sizes -- around 6MB (with
        grayscale fast-start preview). Here's an example of a contrast-blended (4EV range)
        360x65 I just completed, at full resolution, with mid-quality JPEG cube face compression:

        http://turtle.as.arizona.edu/movie/pima_canyon

        Granted this is smaller in size than the equivalent 360x180 would be (thanks to a couple
        of blank cube faces), but surely at 10mm a ~4-5MB full-res pano is easily possible (from
        the roughly 9000x4500 native resolution equirect). Viewer performance is good to
        excellent on files of this size and even modest current hardware (such as my lowly PB G4).
        And I find the ability to zoom a bit further compelling.

        Here's another way to look at it. Monitors are large these days (even laptop screens).
        Here's a table of the maximum zoom (minimum field of view) in degrees which is possible
        before you being upsampling pixels (aka inventing data) in a full-screen view, vs. the
        target equirectangular size:

        screen width:
        equ. size 1024 1280 1600 2048
        ==============================
        3000x 123 154 192 246
        5000x 74 92 115 147
        8000x 46 58 72 92
        10000x 37 46 58 74

        To me, if you zoom out to much more than 80deg, the perspective stretch starts to
        become noticeable and you lose the feeling of being embedded in the scene. So this
        would mean for large monitors, you need 8000x4000 or above. And if you want the
        ability to zoom in to say 40deg for a close look without too much up-resing, you'd want to
        go higher still. Even at 10000x5000, with only a modest 60deg initial field of view you
        aren't "wasting" pixels for people with 1600 pixel wide monitors and above (more and
        more common).

        In an era when people routinely download 5MB music files, 40MB TV shows, etc., is 2MB
        really still a useful metric as an upper limit beyond which no one should tread? And even
        if it is, will it be a year from now, two years from now, or more?

        That said, there are of course other reasons to increase the target pixel-scale from 1.5
        arcmin/pixel to >5 arcmin/pixel (primarily fewer shots == fewer troublesome seams), but
        is "overkill" really the primary issue any more? I should also mention difficulty in
        manipulating ~40MPix images during the pano creation workflow, etc.

        One other thought: the human eye can resolve roughly 1 arcmin details, so to me 1
        arcmin/pixel in a spherical is a natural match, yielding about as much spatial detail as you
        could have seen had you been standing there (discounting of course about a factor of
        10^4-10^6 in contrast perception -- it's hard to match the eye there). You can of course
        go much higher: Max's gigapixel images are down to a few arcsec/pixel, offering far, far
        more detail than you could have seen had you been on the scene. But for truly attempting
        to recreate the feeling and nuance of a location, I believe 1armin/pixel is a useful goal.
        This corresponds roughly to 20k wide equirects.

        JD
      • Sacha Griffin
        These are all good arguments. Things I ve noticed that have influenced my decisions... 1. When shooting 10mm rectanlinear sphericals in areas of high detail
        Message 3 of 17 , Dec 4, 2006
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          These are all good arguments.
          Things I've noticed that have influenced my decisions...
          1. When shooting 10mm rectanlinear sphericals in areas of high detail (ie
          grass), its REALLY difficult to compress down under 7MB without downsampling
          and downsampling. The amount of detail even at the same resolution you would
          take with a fisheye like the sigma f4 is astounding creating a larger file
          at the same resolution.

          2. People don't zoom. It's hard enough to get them to read any instructions
          on the screen for anything. It's quite amazing and disheartening.

          It also depending on the subject. I like the clarity in your shot, am not
          ignorant about zooming, and enjoy the scene. If you did this as a complete
          sphere you'd either need to downsample or living with slow delivery issues.
          For areas, where you are delivering photography for the clients of your
          clients and know you are dealing with people that most likely won't zoom or
          even click and drag despite every blinking instruction... creating sharp 360
          photography downsampled and compressed to 2-3 MB seems perfect to do the
          job.


          Sacha Griffin
          Southern Digital Solutions LLC
          www.southern-digital.com
          www.seeit360.net
          www.ezphotosafe.com
          404-551-4275
          404-731-7798

          -----Original Message-----
          From: yertletertle [mailto:jdsmith@...]
          Sent: Monday, December 04, 2006 1:52 AM
          To: PanoToolsNG@yahoogroups.com
          Subject: [PanoToolsNG] Re: Sigma 10-20 any experiance?

          --- In PanoToolsNG@yahoogroups.com, "Sacha Griffin" <sachagriffin@...>
          wrote:

          > For sphericals a 10mm rectilinear is overkill because it can't not be
          > displayed at full resolution conveniently over the net.
          > This is also true with the 10.5, however the 10.5 is more convenient to
          > shoot with (less shots, less moving subject issues).

          Is this really true anymore? I shoot partial 360's at 18mm on a 1.5 crop
          DSLR, and at full
          resolution (14kpix wide), I can obtain quite reasonable file sizes -- around
          6MB (with
          grayscale fast-start preview). Here's an example of a contrast-blended (4EV
          range)
          360x65 I just completed, at full resolution, with mid-quality JPEG cube face
          compression:

          http://turtle.as.arizona.edu/movie/pima_canyon

          Granted this is smaller in size than the equivalent 360x180 would be (thanks
          to a couple
          of blank cube faces), but surely at 10mm a ~4-5MB full-res pano is easily
          possible (from
          the roughly 9000x4500 native resolution equirect). Viewer performance is
          good to
          excellent on files of this size and even modest current hardware (such as my
          lowly PB G4).
          And I find the ability to zoom a bit further compelling.

          Here's another way to look at it. Monitors are large these days (even
          laptop screens).
          Here's a table of the maximum zoom (minimum field of view) in degrees which
          is possible
          before you being upsampling pixels (aka inventing data) in a full-screen
          view, vs. the
          target equirectangular size:

          screen width:
          equ. size 1024 1280 1600 2048
          ==============================
          3000x 123 154 192 246
          5000x 74 92 115 147
          8000x 46 58 72 92
          10000x 37 46 58 74

          To me, if you zoom out to much more than 80deg, the perspective stretch
          starts to
          become noticeable and you lose the feeling of being embedded in the scene.
          So this
          would mean for large monitors, you need 8000x4000 or above. And if you
          want the
          ability to zoom in to say 40deg for a close look without too much up-resing,
          you'd want to
          go higher still. Even at 10000x5000, with only a modest 60deg initial
          field of view you
          aren't "wasting" pixels for people with 1600 pixel wide monitors and above
          (more and
          more common).

          In an era when people routinely download 5MB music files, 40MB TV shows,
          etc., is 2MB
          really still a useful metric as an upper limit beyond which no one should
          tread? And even
          if it is, will it be a year from now, two years from now, or more?

          That said, there are of course other reasons to increase the target
          pixel-scale from 1.5
          arcmin/pixel to >5 arcmin/pixel (primarily fewer shots == fewer troublesome
          seams), but
          is "overkill" really the primary issue any more? I should also mention
          difficulty in
          manipulating ~40MPix images during the pano creation workflow, etc.

          One other thought: the human eye can resolve roughly 1 arcmin details, so to
          me 1
          arcmin/pixel in a spherical is a natural match, yielding about as much
          spatial detail as you
          could have seen had you been standing there (discounting of course about a
          factor of
          10^4-10^6 in contrast perception -- it's hard to match the eye there). You
          can of course
          go much higher: Max's gigapixel images are down to a few arcsec/pixel,
          offering far, far
          more detail than you could have seen had you been on the scene. But for
          truly attempting
          to recreate the feeling and nuance of a location, I believe 1armin/pixel is
          a useful goal.
          This corresponds roughly to 20k wide equirects.

          JD



          --

          Yahoo! Groups Links
        • JD Smith
          ... Yes, I can see that being an issue. However, with a screen width of 1600 pixels, all you must do is to set the initial zoom field of view to 60 degrees
          Message 4 of 17 , Dec 4, 2006
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            On Mon, 04 Dec 2006 09:32:58 -0500, Sacha Griffin wrote:

            > These are all good arguments.
            > Things I've noticed that have influenced my decisions...
            > 1. When shooting 10mm rectanlinear sphericals in areas of high detail (ie
            > grass), its REALLY difficult to compress down under 7MB without downsampling
            > and downsampling. The amount of detail even at the same resolution you would
            > take with a fisheye like the sigma f4 is astounding creating a larger file
            > at the same resolution.
            >
            > 2. People don't zoom. It's hard enough to get them to read any instructions
            > on the screen for anything. It's quite amazing and disheartening.

            Yes, I can see that being an issue. However, with a screen width of
            1600 pixels, all you must do is to set the initial zoom field of view
            to 60 degrees (hardly "zoomed in"), and you will properly sample *all*
            the detail in a 10000x5000 pano without any more zooming required. In
            the fullscreen era, some of the old maxims aren't as useful.

            > It also depending on the subject. I like the clarity in your shot, am not
            > ignorant about zooming, and enjoy the scene. If you did this as a complete
            > sphere you'd either need to downsample or living with slow delivery issues.
            > For areas, where you are delivering photography for the clients of your
            > clients and know you are dealing with people that most likely won't zoom or
            > even click and drag despite every blinking instruction... creating sharp 360
            > photography downsampled and compressed to 2-3 MB seems perfect to do the
            > job.

            I agree that for a full sphere this would probably have been about
            twice as large, but a full sphere shot at 10mm (instead of 18mm) would
            be about the same or even a bit smaller (5MB, say).

            When delivering hundreds of sphericals is your business, every byte
            counts, and it may indeed be overkill to go beyond 5000x2500, or for
            that matter to use full screen display. But that is based more on
            business decisions than technical decisions. It's perfectly possible
            with today's technology to target ~2 arcmin/pixel (twice the "ideal" 1
            arcmin/pixel I mentioned) without wasting pixels, and without
            requiring the user to zoom in. In fact, I would hazard a guess that
            in the pano I posted, you were already interpolating pixels on your
            screen when you loaded it (primarily because I start reasonably zoomed
            in). Going forward, this will only become easier (as
            bandwidth/processor/graphics cards improve), and more pressing (as
            monitors grow in size and pixel density).

            An interesting side-question is whether and when it will be "easy" to
            acquire panos at the mythical 1 arcmin/pixel. The answer comes in
            considering the pixel pitch of digital camera sensors going forward.
            The maximum pixel pitch of a DSLR today is roughly 180 pixels/mm
            (5.5um pixels). Smaller pixels suffer greater noise (limited by
            photon noise, so no way around it), and out-resolve the image circle
            delivered by even very good lenses, especially at small apertures,
            where diffraction dominates. Here's an interesting take:

            http://www.luminous-landscape.com/essays/pixel-count.shtml

            So, at 180 pixels/mm, to obtain the "ideal" target resolution of 1
            arcmin/pixel, you must shoot at:

            f = 1 arcmin/pixel / 180 pixels/mm * (1 radian/(60*57.3 arcmin)) = 19mm

            On a full-frame sensor, shooting at 19mm offers about 65 degrees of
            view in portrait orientation. Shooting a full sphere will thus
            require two or three rows, and at least 6-8 images around (and many
            more on a 1.5x cropped sensor camera).

            So it seems even with advances in cameras and detectors, the only way
            to resolve 1 arcmin/pixel in the future in a system with single row
            full 360s is to use a camera with a much larger sensors (physically),
            say 70mm x 50mm. This type of sensor is pretty much guaranteed never
            to show up in a consumer or mainstream pro system, simply because it
            would make the entire camera much too large. Here's a 39MPix digital
            back with 6.8um pixels at 50mm x 36mm. Note how large it is:

            http://www.phaseone.com/Content/p1digitalbacks/P%2045.aspx

            JD
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