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zebra sky help

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  • web@drmattnolan.org
    I ve noticed on several of my gigapixel panoramas that there is a vertical banding problem, something like zebra stripes. It seems like every other image or
    Message 1 of 19 , Jul 3, 2011
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      I've noticed on several of my gigapixel panoramas that there is a vertical banding problem, something like zebra stripes. It seems like every other image or so is brighter than the other, so that from left-to-right there is not a seamless sky but rather alternating light and dark. It is subtle, but clear, especially when you zoom out. It shows up in snow fields too.

      Here is an example (not sure whether this works on a Mac):
      http://www.drmattnolan.org/photography/2011/ahab_gigatest/ahabridge_20k.htm

      This is a 20k wide version of a 120k pixel wide original; the zebra pattern is present in the full size original in Photoshop, so its not a resizing or HDview problem. Workflow was 16 bit throughout, from NEF to sRGB tiffs to PSB, then output. The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference, but I havent tested it well either. In PTgui, I tried with and without the exposure optimization tool, with not much difference. I guess I'm thinking I'm either missing some setting in PTgui or some setting on the camera, but before I spend much time with it I was hoping someone might already be familiar with this issue and could let me know the cause?

      Thanks,
      Matt
    • Hans
      ... No cant see it on my Mac. However I guess what it looks like and this is most certainly the shutter curtains that give slightly different exposure at the
      Message 2 of 19 , Jul 3, 2011
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        --- In PanoToolsNG@yahoogroups.com, web@... wrote:
        >
        > I've noticed on several of my gigapixel panoramas that there is a vertical banding problem, something like zebra stripes. It seems like every other image or so is brighter than the other, so that from left-to-right there is not a seamless sky but rather alternating light and dark. It is subtle, but clear, especially when you zoom out. It shows up in snow fields too.
        >
        > Here is an example (not sure whether this works on a Mac):
        > http://www.drmattnolan.org/photography/2011/ahab_gigatest/ahabridge_20k.htm


        No cant see it on my Mac.

        However I guess what it looks like and this is most certainly the shutter curtains that give slightly different exposure at the left/right side.

        I seen it several times from different people and I also stitched a Gigapixel shot with a Nikon that had it.

        The difference needed to get this in a plain sky on a Gigapixel is extremely small and it is quite difficult to adjust as you can not use any vignetting corrections.

        You need to make a manual adjustment mask and run the images with it as an action.

        Hans


        >
        > This is a 20k wide version of a 120k pixel wide original; the zebra pattern is present in the full size original in Photoshop, so its not a resizing or HDview problem. Workflow was 16 bit throughout, from NEF to sRGB tiffs to PSB, then output. The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference, but I havent tested it well either. In PTgui, I tried with and without the exposure optimization tool, with not much difference. I guess I'm thinking I'm either missing some setting in PTgui or some setting on the camera, but before I spend much time with it I was hoping someone might already be familiar with this issue and could let me know the cause?
        >
        > Thanks,
        > Matt
        >
      • jrgen_schrader
        Uh, that looks harsh, not like vignetting. Just to be sure: Could you please check that also WB in the RAWs is set to anything else but Auto . To track down a
        Message 3 of 19 , Jul 3, 2011
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          Uh, that looks harsh, not like vignetting.
          Just to be sure: Could you please check that also WB in the RAWs is set to anything else but "Auto". To track down a possible error in the workflow you might want to give a detailed description from RAW developing through stitching. At which aperture were the images taken?

          Best
          Jürgen

          --- In PanoToolsNG@yahoogroups.com, web@... wrote:
          >
          > I've noticed on several of my gigapixel panoramas that there is a vertical banding problem, something like zebra stripes. It seems like every other image or so is brighter than the other, so that from left-to-right there is not a seamless sky but rather alternating light and dark. It is subtle, but clear, especially when you zoom out. It shows up in snow fields too.
          >
          > Here is an example (not sure whether this works on a Mac):
          > http://www.drmattnolan.org/photography/2011/ahab_gigatest/ahabridge_20k.htm
          >
          > This is a 20k wide version of a 120k pixel wide original; the zebra pattern is present in the full size original in Photoshop, so its not a resizing or HDview problem. Workflow was 16 bit throughout, from NEF to sRGB tiffs to PSB, then output. The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference, but I havent tested it well either. In PTgui, I tried with and without the exposure optimization tool, with not much difference. I guess I'm thinking I'm either missing some setting in PTgui or some setting on the camera, but before I spend much time with it I was hoping someone might already be familiar with this issue and could let me know the cause?
          >
          > Thanks,
          > Matt
          >
        • John Houghton
          ... It s difficult to tell whether the images are in portrait or landscape orientation, so the shutter curtain explanation suggested by Hans may or may not be
          Message 4 of 19 , Jul 3, 2011
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            --- In PanoToolsNG@yahoogroups.com, web@... wrote:
            > The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference,

            It's difficult to tell whether the images are in portrait or landscape orientation, so the shutter curtain explanation suggested by Hans may or may not be a possible explanation. Setting the images side-by-side won't reveal anything. They need to be overlaid as in the PSB file. I would take a small section of 3 or 4 overlapping sky images and limit the investigation to those. You could try a curves adjustment with a L-R graduated selection or mask - in 16 bit mode and with a curves adjustment layer on top to enhance the contrast so that the levels differences are magnified. And you could try different blenders: the Photoshop Auto-Blend Layers often works well.

            John
          • dorindxn
            Is just player s fault, changing the settings from upper right buttons settings, changes the pattern from zebra to triangles, horisontal darks to vertical
            Message 5 of 19 , Jul 3, 2011
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              Is just player's fault, changing the settings from upper right buttons settings, changes the pattern from zebra to triangles, horisontal darks to vertical darks, so on..

              cheers,
              Dorin
              http://www.livepanoramas.com


              --- In PanoToolsNG@yahoogroups.com, "jrgen_schrader" <panorama@...> wrote:
              >
              > Uh, that looks harsh, not like vignetting.
              > Just to be sure: Could you please check that also WB in the RAWs is set to anything else but "Auto". To track down a possible error in the workflow you might want to give a detailed description from RAW developing through stitching. At which aperture were the images taken?
              >
              > Best
              > Jürgen
              >
              > --- In PanoToolsNG@yahoogroups.com, web@ wrote:
              > >
              > > I've noticed on several of my gigapixel panoramas that there is a vertical banding problem, something like zebra stripes. It seems like every other image or so is brighter than the other, so that from left-to-right there is not a seamless sky but rather alternating light and dark. It is subtle, but clear, especially when you zoom out. It shows up in snow fields too.
              > >
              > > Here is an example (not sure whether this works on a Mac):
              > > http://www.drmattnolan.org/photography/2011/ahab_gigatest/ahabridge_20k.htm
              > >
              > > This is a 20k wide version of a 120k pixel wide original; the zebra pattern is present in the full size original in Photoshop, so its not a resizing or HDview problem. Workflow was 16 bit throughout, from NEF to sRGB tiffs to PSB, then output. The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference, but I havent tested it well either. In PTgui, I tried with and without the exposure optimization tool, with not much difference. I guess I'm thinking I'm either missing some setting in PTgui or some setting on the camera, but before I spend much time with it I was hoping someone might already be familiar with this issue and could let me know the cause?
              > >
              > > Thanks,
              > > Matt
              > >
              >
            • web@drmattnolan.org
              Thanks Jürgen. I checked my D300, and WB is set to d-0 , though with raw shooting I m not sure that this setting should influence anything but the preview
              Message 6 of 19 , Jul 3, 2011
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                Thanks Jürgen. I checked my D300, and WB is set to "d-0", though with raw shooting I'm not sure that this setting should influence anything but the preview jpg embedded into it (but 'should' often enough doesnt matter with programming...).

                My workflow is simply to download the raw images, open them in Adobe Bridge, select them and open in Camera Raw, and then tweak them all identically using the Synchronize command until the brightest and darkest images are the best compromise. Then I write them out as 16 bit tiffs and ingest into PTgui.

                One thought I had is wondering how PTgui does exposure blending? That is, if an image is completely blue sky and the adjacent one has a bit of white cloud or dark mountain in it, might PTgui adjust the overall exposure (lighter with a bit of cloud or darker with a bit of mountain) such that the blues no longer match brightness? I guess a test might be to take a single image, duplicate it, arrange it in a row in PTgui, and add black or white corner to some of them and see if the zebra pattern emerges.

                -Matt





                --- In PanoToolsNG@yahoogroups.com, "jrgen_schrader" <panorama@...> wrote:
                >
                > Uh, that looks harsh, not like vignetting.
                > Just to be sure: Could you please check that also WB in the RAWs is set to anything else but "Auto". To track down a possible error in the workflow you might want to give a detailed description from RAW developing through stitching. At which aperture were the images taken?
                >
                > Best
                > Jürgen
                >
                > --- In PanoToolsNG@yahoogroups.com, web@ wrote:
                > >
                > > I've noticed on several of my gigapixel panoramas that there is a vertical banding problem, something like zebra stripes. It seems like every other image or so is brighter than the other, so that from left-to-right there is not a seamless sky but rather alternating light and dark. It is subtle, but clear, especially when you zoom out. It shows up in snow fields too.
                > >
                > > Here is an example (not sure whether this works on a Mac):
                > > http://www.drmattnolan.org/photography/2011/ahab_gigatest/ahabridge_20k.htm
                > >
                > > This is a 20k wide version of a 120k pixel wide original; the zebra pattern is present in the full size original in Photoshop, so its not a resizing or HDview problem. Workflow was 16 bit throughout, from NEF to sRGB tiffs to PSB, then output. The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference, but I havent tested it well either. In PTgui, I tried with and without the exposure optimization tool, with not much difference. I guess I'm thinking I'm either missing some setting in PTgui or some setting on the camera, but before I spend much time with it I was hoping someone might already be familiar with this issue and could let me know the cause?
                > >
                > > Thanks,
                > > Matt
                > >
                >
              • web@drmattnolan.org
                Thanks Dorin. Yes, fooling with the viewer does change the impact of it, but the pattern is present in the unmodified PSB file that comes out of PTgui, so
                Message 7 of 19 , Jul 3, 2011
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                  Thanks Dorin. Yes, fooling with the viewer does change the impact of it, but the pattern is present in the unmodified PSB file that comes out of PTgui, so this cant be the only source.
                  -Matt


                  --- In PanoToolsNG@yahoogroups.com, "dorindxn" <Dorin@...> wrote:
                  >
                  > Is just player's fault, changing the settings from upper right buttons settings, changes the pattern from zebra to triangles, horisontal darks to vertical darks, so on..
                  >
                  > cheers,
                  > Dorin
                  > http://www.livepanoramas.com
                  >
                  >
                  > --- In PanoToolsNG@yahoogroups.com, "jrgen_schrader" <panorama@> wrote:
                  > >
                  > > Uh, that looks harsh, not like vignetting.
                  > > Just to be sure: Could you please check that also WB in the RAWs is set to anything else but "Auto". To track down a possible error in the workflow you might want to give a detailed description from RAW developing through stitching. At which aperture were the images taken?
                  > >
                  > > Best
                  > > Jürgen
                  > >
                  > > --- In PanoToolsNG@yahoogroups.com, web@ wrote:
                  > > >
                  > > > I've noticed on several of my gigapixel panoramas that there is a vertical banding problem, something like zebra stripes. It seems like every other image or so is brighter than the other, so that from left-to-right there is not a seamless sky but rather alternating light and dark. It is subtle, but clear, especially when you zoom out. It shows up in snow fields too.
                  > > >
                  > > > Here is an example (not sure whether this works on a Mac):
                  > > > http://www.drmattnolan.org/photography/2011/ahab_gigatest/ahabridge_20k.htm
                  > > >
                  > > > This is a 20k wide version of a 120k pixel wide original; the zebra pattern is present in the full size original in Photoshop, so its not a resizing or HDview problem. Workflow was 16 bit throughout, from NEF to sRGB tiffs to PSB, then output. The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference, but I havent tested it well either. In PTgui, I tried with and without the exposure optimization tool, with not much difference. I guess I'm thinking I'm either missing some setting in PTgui or some setting on the camera, but before I spend much time with it I was hoping someone might already be familiar with this issue and could let me know the cause?
                  > > >
                  > > > Thanks,
                  > > > Matt
                  > > >
                  > >
                  >
                • web@drmattnolan.org
                  Thanks John. The images were shot in portrait orientation, which I think would orient the shutter movement up and down. I guess the most important thing I ve
                  Message 8 of 19 , Jul 3, 2011
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                    Thanks John. The images were shot in portrait orientation, which I think would orient the shutter movement up and down. I guess the most important thing I've taken away so far is that this is not a common problem, so worth doing some testing on my end.
                    -Matt

                    --- In PanoToolsNG@yahoogroups.com, "John Houghton" <j.houghton@...> wrote:
                    >
                    > --- In PanoToolsNG@yahoogroups.com, web@ wrote:
                    > > The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference,
                    >
                    > It's difficult to tell whether the images are in portrait or landscape orientation, so the shutter curtain explanation suggested by Hans may or may not be a possible explanation. Setting the images side-by-side won't reveal anything. They need to be overlaid as in the PSB file. I would take a small section of 3 or 4 overlapping sky images and limit the investigation to those. You could try a curves adjustment with a L-R graduated selection or mask - in 16 bit mode and with a curves adjustment layer on top to enhance the contrast so that the levels differences are magnified. And you could try different blenders: the Photoshop Auto-Blend Layers often works well.
                    >
                    > John
                    >
                  • Hans
                    ... Well this is a quite common problem and its old as focal plain shutters has existed. Which means it is soon a 100 anniversary as the first Leica was in
                    Message 9 of 19 , Jul 3, 2011
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                      --- In PanoToolsNG@yahoogroups.com, web@... wrote:
                      >
                      > Thanks John. The images were shot in portrait orientation, which I think would orient the shutter movement up and down. I guess the most important thing I've taken away so far is that this is not a common problem, so worth doing some testing on my end.

                      Well this is a quite common problem and its old as focal plain shutters has existed. Which means it is soon a 100 anniversary as the first Leica was in 1913.

                      Almost all shutters today are vertical which means horizontal when you take the images in portrait.

                      As I said the difference in exposure to make this is minimal only 10% is enough as no automatic exposure or vignetting correction helps.

                      I can see you panorama may even have been taken in minus degrees which makes another trigger for it.
                      Remember that even in todays digital world the shutter is still a mechanical thing.

                      I had a lot of this problem on my Pentax 67 back in the 80s.

                      Hans




                      >
                      > --- In PanoToolsNG@yahoogroups.com, "John Houghton" <j.houghton@> wrote:
                      > >
                      > > --- In PanoToolsNG@yahoogroups.com, web@ wrote:
                      > > > The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference,
                      > >
                      > > It's difficult to tell whether the images are in portrait or landscape orientation, so the shutter curtain explanation suggested by Hans may or may not be a possible explanation. Setting the images side-by-side won't reveal anything. They need to be overlaid as in the PSB file. I would take a small section of 3 or 4 overlapping sky images and limit the investigation to those. You could try a curves adjustment with a L-R graduated selection or mask - in 16 bit mode and with a curves adjustment layer on top to enhance the contrast so that the levels differences are magnified. And you could try different blenders: the Photoshop Auto-Blend Layers often works well.
                      > >
                      > > John
                      > >
                      >
                    • Hans
                      ... Here is an example. These are images from a brand new Nikon D7000 http://www.panoramas.dk/technics/bad-shutter-befor-after.jpg The after shows it after
                      Message 10 of 19 , Jul 3, 2011
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                        --- In PanoToolsNG@yahoogroups.com, "Hans" <hans@...> wrote:
                        >
                        >
                        >
                        > --- In PanoToolsNG@yahoogroups.com, web@ wrote:
                        > >
                        > > Thanks John. The images were shot in portrait orientation, which I think would orient the shutter movement up and down. I guess the most important thing I've taken away so far is that this is not a common problem, so worth doing some testing on my end.
                        >
                        > Well this is a quite common problem and its old as focal plain shutters has existed. Which means it is soon a 100 anniversary as the first Leica was in 1913.
                        >
                        > Almost all shutters today are vertical which means horizontal when you take the images in portrait.
                        >
                        > As I said the difference in exposure to make this is minimal only 10% is enough as no automatic exposure or vignetting correction helps.
                        >
                        > I can see you panorama may even have been taken in minus degrees which makes another trigger for it.
                        > Remember that even in todays digital world the shutter is still a mechanical thing.
                        >
                        > I had a lot of this problem on my Pentax 67 back in the 80s.
                        >
                        > Hans

                        Here is an example. These are images from a brand new Nikon D7000
                        http://www.panoramas.dk/technics/bad-shutter-befor-after.jpg

                        The after shows it after applying graduation adjustment in photoshop.

                        Here is how the stitch looks from the not adjusted.
                        http://www.panoramas.dk/technics/bad-shutter-result.jpg

                        As you can see the difference is very small just 3% but the result on the stitched is large.

                        You can not see that there is a small exposure difference without placing the images side by side.

                        Hans





                        >
                        >
                        >
                        >
                        > >
                        > > --- In PanoToolsNG@yahoogroups.com, "John Houghton" <j.houghton@> wrote:
                        > > >
                        > > > --- In PanoToolsNG@yahoogroups.com, web@ wrote:
                        > > > > The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference,
                        > > >
                        > > > It's difficult to tell whether the images are in portrait or landscape orientation, so the shutter curtain explanation suggested by Hans may or may not be a possible explanation. Setting the images side-by-side won't reveal anything. They need to be overlaid as in the PSB file. I would take a small section of 3 or 4 overlapping sky images and limit the investigation to those. You could try a curves adjustment with a L-R graduated selection or mask - in 16 bit mode and with a curves adjustment layer on top to enhance the contrast so that the levels differences are magnified. And you could try different blenders: the Photoshop Auto-Blend Layers often works well.
                        > > >
                        > > > John
                        > > >
                        > >
                        >
                      • Ormar
                        Do you tried to convert images with other converter (not ACR or Lightroom) I had similar problem and moving to Capture One fixed the problem. By my experience
                        Message 11 of 19 , Jul 3, 2011
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                          Do you tried to convert images with other converter (not ACR or Lightroom) I had similar problem and moving to Capture One fixed the problem. By my experience ACR will do it, if you use strong enhancements.
                        • Erik Krause
                          ... Matt, what exposure time did you use? Hans is right about the shutter speed differences. However, this effect gets worse if you use shorter exposures. If
                          Message 12 of 19 , Jul 3, 2011
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                            Am 03.07.2011 20:20, schrieb Hans:
                            > Well this is a quite common problem and its old as focal plain
                            > shutters has existed. Which means it is soon a 100 anniversary as
                            > the first Leica was in 1913.

                            > Almost all shutters today are vertical which means horizontal when
                            > you take the images in portrait.

                            > As I said the difference in exposure to make this is minimal only 10%
                            > is enough as no automatic exposure or vignetting correction helps.

                            Matt, what exposure time did you use? Hans is right about the shutter
                            speed differences. However, this effect gets worse if you use shorter
                            exposures. If you use longer exposures where the total opening time of
                            the shutter is much longer than the actual shutter movement it shouldn't
                            play a role anymore.

                            The time one shutter needs to move is approximately half the shortest
                            time that still allows flash exposure (with a conventional flash - no
                            tricks like high speed sync). The reason is, that the shutter needs to
                            be fully open before the flash fires and only after that can the closing
                            curtain start.

                            So if you shoot at this exposure time (or slower) you shouldn't get the
                            effect. However, additional care must be taken to avoide camera shake at
                            slow speeds with long lenses...

                            --
                            Erik Krause
                            http://www.erik-krause.de
                          • Erik Krause
                            ... Brand new? The effect in those images seems not to be simple speed differences in opening and closing curtain, it looks like the shutter hangs in some
                            Message 13 of 19 , Jul 3, 2011
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                              Am 03.07.2011 20:39, schrieb Hans:
                              > Here is an example. These are images from a brand new Nikon D7000
                              > http://www.panoramas.dk/technics/bad-shutter-befor-after.jpg

                              Brand new? The effect in those images seems not to be simple speed
                              differences in opening and closing curtain, it looks like the shutter
                              hangs in some point.

                              I had this in my very old (analog) EOS 600 and the reason was a piece of
                              foam rubber intended to brake the shutter. This piece disintegrated into
                              a gluey smear which sticked the shutter blades together - a common
                              problem for older EOS cameras. I managed to clean the shutter with some
                              cleaning solvent and the camera worked ok for another couple of years.

                              If this happens in a brand new camera it should be returned in my opinion.

                              --
                              Erik Krause
                              http://www.erik-krause.de
                            • Mark Fink
                              Hi Matt, I don t know if this is contributing to the problem, but why are you converting to sRGB TIFF? I convert to ProPhoto TIFF based on something I heard
                              Message 14 of 19 , Jul 4, 2011
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                                Hi Matt,

                                I don't know if this is contributing to the problem, but why are you
                                converting to sRGB TIFF? I convert to ProPhoto TIFF based on something I
                                heard this guy say a couple years ago:

                                http://schewephoto.com/sRGB-VS-PPRGB/

                                It would be interesting to redo a section of your pano in ProPhoto and
                                compare via overlay with your sRGB.

                                Mark

                                -----Original Message-----
                                From: PanoToolsNG@yahoogroups.com [mailto:PanoToolsNG@yahoogroups.com] On
                                Behalf Of web@...
                                Sent: Sunday, July 03, 2011 6:46 AM
                                To: PanoToolsNG@yahoogroups.com
                                Subject: [PanoToolsNG] zebra sky help

                                I've noticed on several of my gigapixel panoramas that there is a vertical
                                banding problem, something like zebra stripes. It seems like every other
                                image or so is brighter than the other, so that from left-to-right there is
                                not a seamless sky but rather alternating light and dark. It is subtle, but
                                clear, especially when you zoom out. It shows up in snow fields too.

                                Here is an example (not sure whether this works on a Mac):
                                http://www.drmattnolan.org/photography/2011/ahab_gigatest/ahabridge_20k.htm

                                This is a 20k wide version of a 120k pixel wide original; the zebra pattern
                                is present in the full size original in Photoshop, so its not a resizing or
                                HDview problem. Workflow was 16 bit throughout, from NEF to sRGB tiffs to
                                PSB, then output. The images were shot with a D300 in manual mode with
                                nothing left to chance (that I know of... but definitely not shutter speed,
                                aperture or iso... not sure what else is left when shooting raw) and
                                processed identically in ACR to tiff. Putting the tiffs side by side I dont
                                notice an exposure difference, but I havent tested it well either. In
                                PTgui, I tried with and without the exposure optimization tool, with not
                                much difference. I guess I'm thinking I'm either missing some setting in
                                PTgui or some setting on the camera, but before I spend much time with it I
                                was hoping someone might already be familiar with this issue and could let
                                me know the cause?

                                Thanks,
                                Matt





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                              • web@drmattnolan.org
                                Thanks Hans. I still havent done any testing of my images, but it does seem that you have identified the issue. It s a bit distressing, as this panorama,
                                Message 15 of 19 , Jul 4, 2011
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                                  Thanks Hans. I still havent done any testing of my images, but it does seem that you have identified the issue. It's a bit distressing, as this panorama, like many others of mine, has about 400 images in it, and even if I had the time, I'm not sure I'd now where to begin, as if I understand correctly this is a somewhat random process affecting each image differently. If I understood your fix correctly, it was not a simply expsoure adjustment applied to the whole image, but rather a gradient?
                                  -Matt



                                  --- In PanoToolsNG@yahoogroups.com, "Hans" <hans@...> wrote:
                                  >
                                  >
                                  >
                                  > --- In PanoToolsNG@yahoogroups.com, "Hans" <hans@> wrote:
                                  > >
                                  > >
                                  > >
                                  > > --- In PanoToolsNG@yahoogroups.com, web@ wrote:
                                  > > >
                                  > > > Thanks John. The images were shot in portrait orientation, which I think would orient the shutter movement up and down. I guess the most important thing I've taken away so far is that this is not a common problem, so worth doing some testing on my end.
                                  > >
                                  > > Well this is a quite common problem and its old as focal plain shutters has existed. Which means it is soon a 100 anniversary as the first Leica was in 1913.
                                  > >
                                  > > Almost all shutters today are vertical which means horizontal when you take the images in portrait.
                                  > >
                                  > > As I said the difference in exposure to make this is minimal only 10% is enough as no automatic exposure or vignetting correction helps.
                                  > >
                                  > > I can see you panorama may even have been taken in minus degrees which makes another trigger for it.
                                  > > Remember that even in todays digital world the shutter is still a mechanical thing.
                                  > >
                                  > > I had a lot of this problem on my Pentax 67 back in the 80s.
                                  > >
                                  > > Hans
                                  >
                                  > Here is an example. These are images from a brand new Nikon D7000
                                  > http://www.panoramas.dk/technics/bad-shutter-befor-after.jpg
                                  >
                                  > The after shows it after applying graduation adjustment in photoshop.
                                  >
                                  > Here is how the stitch looks from the not adjusted.
                                  > http://www.panoramas.dk/technics/bad-shutter-result.jpg
                                  >
                                  > As you can see the difference is very small just 3% but the result on the stitched is large.
                                  >
                                  > You can not see that there is a small exposure difference without placing the images side by side.
                                  >
                                  > Hans
                                  >
                                  >
                                  >
                                  >
                                  >
                                  > >
                                  > >
                                  > >
                                  > >
                                  > > >
                                  > > > --- In PanoToolsNG@yahoogroups.com, "John Houghton" <j.houghton@> wrote:
                                  > > > >
                                  > > > > --- In PanoToolsNG@yahoogroups.com, web@ wrote:
                                  > > > > > The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference,
                                  > > > >
                                  > > > > It's difficult to tell whether the images are in portrait or landscape orientation, so the shutter curtain explanation suggested by Hans may or may not be a possible explanation. Setting the images side-by-side won't reveal anything. They need to be overlaid as in the PSB file. I would take a small section of 3 or 4 overlapping sky images and limit the investigation to those. You could try a curves adjustment with a L-R graduated selection or mask - in 16 bit mode and with a curves adjustment layer on top to enhance the contrast so that the levels differences are magnified. And you could try different blenders: the Photoshop Auto-Blend Layers often works well.
                                  > > > >
                                  > > > > John
                                  > > > >
                                  > > >
                                  > >
                                  >
                                • web@drmattnolan.org
                                  Erik, I used a shutter speed of 1/1600s, f/7.1, ISO 200. So I cant go any lower ISO, but I could decrease f/ a stop and slow the shutter by half, but beyond
                                  Message 16 of 19 , Jul 4, 2011
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                                    Erik,

                                    I used a shutter speed of 1/1600s, f/7.1, ISO 200. So I cant go any lower ISO, but I could decrease f/ a stop and slow the shutter by half, but beyond that I guess I would have to go to a neutral density filter? Seems counter-intuitive, but rationally it makes sense that a small percent error in time has less impact with a longer interval. Certainly it seems worth maximing shutter speed in the future.

                                    I do a lot of vertical aerial photography too, I'd hate to have to slow down shutter speeds to make better mosaics, as camera shake here is a major concern...!

                                    -Matt


                                    --- In PanoToolsNG@yahoogroups.com, Erik Krause <erik.krause@...> wrote:
                                    >
                                    > Am 03.07.2011 20:20, schrieb Hans:
                                    > > Well this is a quite common problem and its old as focal plain
                                    > > shutters has existed. Which means it is soon a 100 anniversary as
                                    > > the first Leica was in 1913.
                                    >
                                    > > Almost all shutters today are vertical which means horizontal when
                                    > > you take the images in portrait.
                                    >
                                    > > As I said the difference in exposure to make this is minimal only 10%
                                    > > is enough as no automatic exposure or vignetting correction helps.
                                    >
                                    > Matt, what exposure time did you use? Hans is right about the shutter
                                    > speed differences. However, this effect gets worse if you use shorter
                                    > exposures. If you use longer exposures where the total opening time of
                                    > the shutter is much longer than the actual shutter movement it shouldn't
                                    > play a role anymore.
                                    >
                                    > The time one shutter needs to move is approximately half the shortest
                                    > time that still allows flash exposure (with a conventional flash - no
                                    > tricks like high speed sync). The reason is, that the shutter needs to
                                    > be fully open before the flash fires and only after that can the closing
                                    > curtain start.
                                    >
                                    > So if you shoot at this exposure time (or slower) you shouldn't get the
                                    > effect. However, additional care must be taken to avoide camera shake at
                                    > slow speeds with long lenses...
                                    >
                                    > --
                                    > Erik Krause
                                    > http://www.erik-krause.de
                                    >
                                  • Hans
                                    ... I actually used the Camera Raw adjustment brush when converting them. However a gradient on the converted tifs might work just as good. It takes some
                                    Message 17 of 19 , Jul 4, 2011
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                                      --- In PanoToolsNG@yahoogroups.com, web@... wrote:
                                      >
                                      >
                                      > Thanks Hans. I still havent done any testing of my images, but it does seem that you have identified the issue. It's a bit distressing, as this panorama, like many others of mine, has about 400 images in it, and even if I had the time, I'm not sure I'd now where to begin, as if I understand correctly this is a somewhat random process affecting each image differently. If I understood your fix correctly, it was not a simply expsoure adjustment applied to the whole image, but rather a gradient?


                                      I actually used the Camera Raw adjustment brush when converting them.
                                      However a gradient on the converted tifs might work just as good.

                                      It takes some experiments to find the correct amount.

                                      Hans



                                      > -Matt
                                      >
                                      >
                                      >
                                      > --- In PanoToolsNG@yahoogroups.com, "Hans" <hans@> wrote:
                                      > >
                                      > >
                                      > >
                                      > > --- In PanoToolsNG@yahoogroups.com, "Hans" <hans@> wrote:
                                      > > >
                                      > > >
                                      > > >
                                      > > > --- In PanoToolsNG@yahoogroups.com, web@ wrote:
                                      > > > >
                                      > > > > Thanks John. The images were shot in portrait orientation, which I think would orient the shutter movement up and down. I guess the most important thing I've taken away so far is that this is not a common problem, so worth doing some testing on my end.
                                      > > >
                                      > > > Well this is a quite common problem and its old as focal plain shutters has existed. Which means it is soon a 100 anniversary as the first Leica was in 1913.
                                      > > >
                                      > > > Almost all shutters today are vertical which means horizontal when you take the images in portrait.
                                      > > >
                                      > > > As I said the difference in exposure to make this is minimal only 10% is enough as no automatic exposure or vignetting correction helps.
                                      > > >
                                      > > > I can see you panorama may even have been taken in minus degrees which makes another trigger for it.
                                      > > > Remember that even in todays digital world the shutter is still a mechanical thing.
                                      > > >
                                      > > > I had a lot of this problem on my Pentax 67 back in the 80s.
                                      > > >
                                      > > > Hans
                                      > >
                                      > > Here is an example. These are images from a brand new Nikon D7000
                                      > > http://www.panoramas.dk/technics/bad-shutter-befor-after.jpg
                                      > >
                                      > > The after shows it after applying graduation adjustment in photoshop.
                                      > >
                                      > > Here is how the stitch looks from the not adjusted.
                                      > > http://www.panoramas.dk/technics/bad-shutter-result.jpg
                                      > >
                                      > > As you can see the difference is very small just 3% but the result on the stitched is large.
                                      > >
                                      > > You can not see that there is a small exposure difference without placing the images side by side.
                                      > >
                                      > > Hans
                                      > >
                                      > >
                                      > >
                                      > >
                                      > >
                                      > > >
                                      > > >
                                      > > >
                                      > > >
                                      > > > >
                                      > > > > --- In PanoToolsNG@yahoogroups.com, "John Houghton" <j.houghton@> wrote:
                                      > > > > >
                                      > > > > > --- In PanoToolsNG@yahoogroups.com, web@ wrote:
                                      > > > > > > The images were shot with a D300 in manual mode with nothing left to chance (that I know of... but definitely not shutter speed, aperture or iso... not sure what else is left when shooting raw) and processed identically in ACR to tiff. Putting the tiffs side by side I dont notice an exposure difference,
                                      > > > > >
                                      > > > > > It's difficult to tell whether the images are in portrait or landscape orientation, so the shutter curtain explanation suggested by Hans may or may not be a possible explanation. Setting the images side-by-side won't reveal anything. They need to be overlaid as in the PSB file. I would take a small section of 3 or 4 overlapping sky images and limit the investigation to those. You could try a curves adjustment with a L-R graduated selection or mask - in 16 bit mode and with a curves adjustment layer on top to enhance the contrast so that the levels differences are magnified. And you could try different blenders: the Photoshop Auto-Blend Layers often works well.
                                      > > > > >
                                      > > > > > John
                                      > > > > >
                                      > > > >
                                      > > >
                                      > >
                                      >
                                    • web@drmattnolan.org
                                      Mark, For a while I had been using Prophoto too, based on some books and articles I read. However, I found it in the end to be more trouble than it was worth.
                                      Message 18 of 19 , Jul 4, 2011
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                                        Mark,

                                        For a while I had been using Prophoto too, based on some books and articles I read. However, I found it in the end to be more trouble than it was worth. In particular, I was always getting color space mismatches for web stuff, which gave images a greenish cast when trying to display as sRGB. Often I wouldnt catch it, then I'd have to reupload something. It was also causing problems printing, trying to get hardware and software to honor color space choices and also hoping the printer could print all of the colors without swapping some. Plus my eye isnt critical enough, I'm pretty happy if what comes out on the printer looks reasonably close to the screen. And since my photography is primarily in glacier regions, there's not a lot of color there. So a long winded answer, but the short version is just convenience and one less thing to screw up or screw things up. But once I start testing the solution to the zebra pattern, I will test color space for completeness.

                                        Thanks,
                                        Matt


                                        --- In PanoToolsNG@yahoogroups.com, "Mark Fink" <markdfink@...> wrote:
                                        >
                                        > Hi Matt,
                                        >
                                        > I don't know if this is contributing to the problem, but why are you
                                        > converting to sRGB TIFF? I convert to ProPhoto TIFF based on something I
                                        > heard this guy say a couple years ago:
                                        >
                                        > http://schewephoto.com/sRGB-VS-PPRGB/
                                        >
                                        > It would be interesting to redo a section of your pano in ProPhoto and
                                        > compare via overlay with your sRGB.
                                        >
                                        > Mark
                                        >
                                        > -----Original Message-----
                                        > From: PanoToolsNG@yahoogroups.com [mailto:PanoToolsNG@yahoogroups.com] On
                                        > Behalf Of web@...
                                        > Sent: Sunday, July 03, 2011 6:46 AM
                                        > To: PanoToolsNG@yahoogroups.com
                                        > Subject: [PanoToolsNG] zebra sky help
                                        >
                                        > I've noticed on several of my gigapixel panoramas that there is a vertical
                                        > banding problem, something like zebra stripes. It seems like every other
                                        > image or so is brighter than the other, so that from left-to-right there is
                                        > not a seamless sky but rather alternating light and dark. It is subtle, but
                                        > clear, especially when you zoom out. It shows up in snow fields too.
                                        >
                                        > Here is an example (not sure whether this works on a Mac):
                                        > http://www.drmattnolan.org/photography/2011/ahab_gigatest/ahabridge_20k.htm
                                        >
                                        > This is a 20k wide version of a 120k pixel wide original; the zebra pattern
                                        > is present in the full size original in Photoshop, so its not a resizing or
                                        > HDview problem. Workflow was 16 bit throughout, from NEF to sRGB tiffs to
                                        > PSB, then output. The images were shot with a D300 in manual mode with
                                        > nothing left to chance (that I know of... but definitely not shutter speed,
                                        > aperture or iso... not sure what else is left when shooting raw) and
                                        > processed identically in ACR to tiff. Putting the tiffs side by side I dont
                                        > notice an exposure difference, but I havent tested it well either. In
                                        > PTgui, I tried with and without the exposure optimization tool, with not
                                        > much difference. I guess I'm thinking I'm either missing some setting in
                                        > PTgui or some setting on the camera, but before I spend much time with it I
                                        > was hoping someone might already be familiar with this issue and could let
                                        > me know the cause?
                                        >
                                        > Thanks,
                                        > Matt
                                        >
                                        >
                                        >
                                        >
                                        >
                                        > ------------------------------------
                                        >
                                        > --
                                        >
                                        >
                                        >
                                        >
                                        > -----
                                        > No virus found in this message.
                                        > Checked by AVG - www.avg.com
                                        > Version: 10.0.1388 / Virus Database: 1516/3741 - Release Date: 07/03/11
                                        >
                                      • Erik Krause
                                        ... In Photoshop: Use a levels or brightness adjustment layer and paint a gradient in the associated mask with the gradient tool. You can use the color sampler
                                        Message 19 of 19 , Jul 4, 2011
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                                          Am 04.07.2011 20:13, schrieb web@...:
                                          > If I understood your fix correctly, it was not a simply expsoure
                                          > adjustment applied to the whole image, but rather a gradient?

                                          In Photoshop: Use a levels or brightness adjustment layer and paint a
                                          gradient in the associated mask with the gradient tool. You can use the
                                          color sampler tool to measure the brightness values in the same point in
                                          the neighboring image. Once you found good values record the whole
                                          process as an action and create a droplet from it. You then can drop all
                                          your 400 files on it and let the computer process them while you do
                                          something different.

                                          You can even use a flat field: shoot an evenly lit surface with same
                                          aperture and exposure settings (you can rotate the camera, shoot several
                                          and average later). Do an auto levels on the resulting image and use the
                                          result as a mask. To find the correct adjustment try on the original
                                          image until lighting is perfectly even. To see this better you can put
                                          an auto levels layer above.

                                          --
                                          Erik Krause
                                          http://www.erik-krause.de
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