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RE: [PanoToolsNG] Re: Sony announce 25Mp 35mm sensor

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  • Keith Martin
    ... But then, a full-frame sensor camera does mean working with different lenses to get the equivalent effect. So a rough equivalent of the 10.5mm would be
    Message 1 of 15 , Feb 1, 2008
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      Sometime around 1/2/08 (at 01:42 -0800) Paul D. DeRocco said:

      > > From: Erik Krause
      >>
      >> ...then 10MP on a crop factor 1.6 sensor is beyond the resolution of
      >> any fisheye, too. 25MP on a full frame sensor has the same absolute
      >> resolution (pixel density) like a 10MP sensor at crop faktor 1.6
      >
      >Probably. Even on my 6Mp 10D, which is a 1.6x crop sensor, I can see a lot
      >of CA near the edges, so it's obvious that I wouldn't be getting any more
      >sharpness if I stuck it on my 10Mp 40D. And a 25MP FF sensor would probably
      >be even worse, because it reaches into the worst part of the lens.

      But then, a full-frame sensor camera does mean working with different
      lenses to get the equivalent effect. So a rough equivalent of the
      10.5mm would be 16mm, wouldn't it? Something like the old 16mm
      fisheye that I used briefly on my old Canon A1. Assuming the
      manufacturing and glass quality was similar, that would give
      approximately the same view but reduced chromatic abberation.
      (Slightly reduced depth of field too, but that's physics for ya!)

      I don't think it is really a matter of being beyond the resolution of
      a fisheye, as that's just analog-world optics. The Sigma 8mm and
      Nikon 10.5mm fisheyes are designed to produce acceptable images on a
      cropped-area sensor, and trying to capture an image using a broader
      part of the image means going beyond the design intentions. So...
      isn't the important thing simply using a lens that is actually meant
      to cover a full-frame sensor?

      (I think that's what you meant in your first post, but I wasn't sure...)

      k
    • Erik Krause
      ... This is what I would suspect people to do with a full frame sensor, yes. But apparently most of them use a 10.5mm or even 8mm lens in order to need less
      Message 2 of 15 , Feb 1, 2008
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        On Friday, February 01, 2008 at 10:41, Keith Martin wrote:

        > But then, a full-frame sensor camera does mean working with different
        > lenses to get the equivalent effect. So a rough equivalent of the
        > 10.5mm would be 16mm, wouldn't it? Something like the old 16mm
        > fisheye that I used briefly on my old Canon A1.

        This is what I would suspect people to do with a full frame sensor,
        yes. But apparently most of them use a 10.5mm or even 8mm lens in
        order to need less shots. With a 25MP full frame sensor they would
        get roughly the same output resolution as with the same lens on a
        10MP crop factor camera.

        > Assuming the manufacturing and glass quality was similar, that would
        > give approximately the same view but reduced chromatic abberation.

        Yes, of course. But you always can go for even higher quality using
        longer lenses and more shots...

        > (Slightly reduced depth of field too, but that's physics for ya!)

        There is a frequent misunderstanding about DOF and spherical
        panoramas mostly because people use DOF values intended for single
        printed images as a comparison. For spherical you have to calculate
        differently: http://wiki.panotools.org/Depth_of_Field

        > I don't think it is really a matter of being beyond the resolution of
        > a fisheye, as that's just analog-world optics. The Sigma 8mm and
        > Nikon 10.5mm fisheyes are designed to produce acceptable images on a
        > cropped-area sensor, and trying to capture an image using a broader
        > part of the image means going beyond the design intentions.

        The corners of a crop factor 1.5 image from a 10.5mm lens are very
        close to the outer image circle. Hence if you talk about fisheyes you
        can't simply say "designed for...". Anyone should know that close to
        the image circle there is a lower resolution, not only due to lens
        design flaws but due to the fisheye mapping.

        > So... isn't the important thing simply using a lens that is actually
        > meant to cover a full-frame sensor?

        The pre-digital Sigma 8mm lenses where meant to cover a full-frame
        sensor. Nevertheless the image quality was bad near the image circle.

        You could use it on a full-frame sensor for a 3-around workflow,
        where each image contributes about 120° - which is pretty inside the
        image circle and (coincidentally!) a crop by 1.5

        Same applies if you use a 10.5mm lens on a full-frame. In a 3-around
        workflow you more or less use only the parts visible on a 1.5 crop
        sensor anyway. The ecxess parts are only necessary because you need
        some overlap to find control points.

        best regards


        Erik Krause
        http://www.erik-krause.de
      • Keith Martin
        ... Got it. Although really it is is lower *quality* that we re talking about. Resolution, although related in a sense, means something slightly different. At
        Message 3 of 15 , Feb 1, 2008
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          Sometime around 1/2/08 (at 13:35 +0100) Erik Krause said:

          >close to the image circle there is a lower resolution, not
          >only due to lens design flaws but due to the fisheye mapping.

          Got it. Although really it is is lower *quality* that we're talking
          about. Resolution, although related in a sense, means something
          slightly different. At least, with digital images it is used to refer
          to the sensors and the final pixels.

          Thanks for the further info and the DoF link! I was thinking in terms
          of individual shots, but that's interesting data on that wiki. Stuff
          for me to ponder. :-)

          k
        • mrjimbo
          Keith, I m not a rocket scientist but did learn that the delay for the introduction of teh Betterlight new 10k scan back was all about that no lenses resolved
          Message 4 of 15 , Feb 1, 2008
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            Keith,
            I'm not a rocket scientist but did learn that the delay for the introduction of teh Betterlight new 10k scan back was all about that no lenses resolved what it would do properly.. Some how they did get to a compromise and did release the back.. In my converstaions with them at that time they spoke of the issues related to that level of resolving using optics.. Further we must realize that today optics are multi part.. So it's probably not just a matter of saying make another one that does it.. In the smaller sensors they have been packing more and more pixels.. but as spoken in these posts that has been at a price.. So it makes sense to make larger sensors..so the info that is captured isn't shrunk as much. The optics are actually doing a conversion...making a big image fit on a small sensor.. It appears that what we are experiencing is degradiation when we get to a certain threhshold at out current optical technology. The present answer is larger cameras it seems.. So tommorrows Nikon may look like my Pentax 6x7 with a face lift and a Nikon logo on it ( hopefully a little lighter too)....or a new version of a Sinar 8x10 with a fixed sensor in the back of it.with large pixel sizes... Whooo Hooo.

            jimbo


            ----- Original Message -----
            From: Keith Martin
            To: PanoToolsNG@yahoogroups.com
            Sent: Friday, February 01, 2008 3:41 AM
            Subject: RE: [PanoToolsNG] Re: Sony announce 25Mp 35mm sensor


            Sometime around 1/2/08 (at 01:42 -0800) Paul D. DeRocco said:

            > > From: Erik Krause
            >>
            >> ...then 10MP on a crop factor 1.6 sensor is beyond the resolution of
            >> any fisheye, too. 25MP on a full frame sensor has the same absolute
            >> resolution (pixel density) like a 10MP sensor at crop faktor 1.6
            >
            >Probably. Even on my 6Mp 10D, which is a 1.6x crop sensor, I can see a lot
            >of CA near the edges, so it's obvious that I wouldn't be getting any more
            >sharpness if I stuck it on my 10Mp 40D. And a 25MP FF sensor would probably
            >be even worse, because it reaches into the worst part of the lens.

            But then, a full-frame sensor camera does mean working with different
            lenses to get the equivalent effect. So a rough equivalent of the
            10.5mm would be 16mm, wouldn't it? Something like the old 16mm
            fisheye that I used briefly on my old Canon A1. Assuming the
            manufacturing and glass quality was similar, that would give
            approximately the same view but reduced chromatic abberation.
            (Slightly reduced depth of field too, but that's physics for ya!)

            I don't think it is really a matter of being beyond the resolution of
            a fisheye, as that's just analog-world optics. The Sigma 8mm and
            Nikon 10.5mm fisheyes are designed to produce acceptable images on a
            cropped-area sensor, and trying to capture an image using a broader
            part of the image means going beyond the design intentions. So...
            isn't the important thing simply using a lens that is actually meant
            to cover a full-frame sensor?

            (I think that's what you meant in your first post, but I wasn't sure...)

            k




            [Non-text portions of this message have been removed]
          • Fabio Bustamante
            Hey Carel, So in theory it would be possible to develop a ~4mp image from a 12.8mp RAW file, is it right? Have you ever tried this? How different in practice
            Message 5 of 15 , Feb 2, 2008
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              Hey Carel,

              So in theory it would be possible to develop a ~4mp image from a 12.8mp
              RAW file, is it right? Have you ever tried this? How different in
              practice would that be from reducing a 12.8mp picture to a 4mp size with
              a good interpolator?

              I can hardly imagine a 4mp image that surpasses it's 12.8mp version in
              any way...

              Is this really used in star photography?
              >
              > One could use all these pixels in combination with DCRaw in the Super-pixel
              > mode to circumvent the Bayer matrix induced artifacts. The main disadvantage
              > of the super-pixel method is that you end up with an image that is only
              > 1/4th size of the original, so with this sensor you would end up with a
              > 6Mpixel image, but more detailed image.
              > http://deepskystacker.free.fr/english/technical.htm#rawdecod
              >
              > Carel
              >
            • Carel
              ... No, it would not surpass the original sized quality, but might be an interesting way to use this overkill of 24Mpixels for web purposes. I only have 5D
              Message 6 of 15 , Feb 2, 2008
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                Fabio Bustamante-2 wrote:
                >
                > Hey Carel,
                >
                > So in theory it would be possible to develop a ~4mp image from a 12.8mp
                > RAW file, is it right? Have you ever tried this? How different in
                > practice would that be from reducing a 12.8mp picture to a 4mp size with
                > a good interpolator?
                >
                > I can hardly imagine a 4mp image that surpasses it's 12.8mp version in
                > any way...
                >
                > Is this really used in star photography?
                >
                >

                No, it would not surpass the original sized quality, but might be an
                interesting way to use this overkill of 24Mpixels for web purposes. I only
                have 5D images, but a test is on the way. I will use the super-pixel method
                with DCRaw versus ACR. My reasoning was along the lines of Bernhard Vogl,
                his complaints about the shortcomings of the Bayer array and his observation
                that one retains more detail when downsizing an image that was taken with a
                longer lens to the size of the same image taken with a shorter lens. But
                maybe that is not a good analogy.

                >Is this really used in star photography?

                The inclusion of this method in DeepSkyStacker would indicate so. When I
                asked about this on my recent visit to the Mt Wilson Observatory, it did not
                seem to ring a bell, while the recently discussed method of getting a
                sharper image by using a slightly misalligned stack of images ("dribbling")
                did.

                Carel
                --
                View this message in context: http://www.nabble.com/Sony-announce-25Mp-35mm-sensor-tp15207204p15249800.html
                Sent from the PanoToolsNG mailing list archive at Nabble.com.
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