Bad stitch of zenith
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  1. Bad stitch of zenith

    #1
    Niklas

    Hi!

    I use Canon EOS 5D with Canon EF 15 mm f/2.8 Fisheye on Nodal Ninja 5 L. I have used the camera settings 53,5 for the lower rail and 79,5 for the upper rail (as suggested on the camera setting page). When I stitch the images in PTGui the stitch between the zenith image and the others are horrible. If i leave out the zenith image I get a good stitch.

    Does anyone have suggestions on what I should change in order to get it right. I have tried at least ten times with the same result.

    Best regards,

    Niklas
  2. Re: Bad stitch of zenith

    #2

    Hey Niklas,
    Welcome to the forum.
    Not sure if your problem is related to PTGui or if you have the wrong settings with your gear. The settings on our settings page are from other NN users and unless we hear to contrary we tend to assume they are correct. Because you get a good stitch leaving out the zenith I would also further believe the settings are true (which is our primary concern).
    That said I tend to lean towards this being software issue and unfortunately I am not proficiency enough with PTGui to offer support for the software.
    Would you be able to send over the sample images so I can give a go at stitching them? If so send to bill [at] nodalninja .com.
    Thanks
    Bill
  3. Re: Bad stitch of zenith

    #3
    Niklas

    Thank you!

    I think you are right in assuming there's something wrong with the software. I managed to get a decent stitch after realigning the images a couple of times. Why that would make a difference I am not sure, but I will continue testing. :-)

    Best regards,

    Niklas
  4. Re: Bad stitch of zenith

    #4

    For software issues try looking at PTGui's website
    http://www.ptgui.com/examples/

    Also other excellent forums with lots of PTGui users are:
    http://www.nabble.com/PanoToolsNG-f15658.html
    http://www.panoguide.com/forums/
    Hope this helps - keeps us posted on how you go.
    Thanks
    Bill
  5. Re: Bad stitch of zenith

    #5
    Users Country Flag Macro's Avatar
    Join Date: Apr 2008
    Location: South Korea
    Posts: 80

    Hi Niklas,

    I had a similar problem recently where the zenith image would not stitch at all. Without the zenith, everything stitched great. The zenith was a circular domed church ceiling with several repeating patterns that confused PTGui. PTGui basically couldn't figure out which ones matched since they all looked the same. When I added manual control points between the zenith and EACH image in the row below, then everything fell into place beautifully.

    David
  6. Re: Bad stitch of zenith

    #6
    mediavets

    Quote Originally Posted by Niklas View Post
    Hi!

    I use Canon EOS 5D with Canon EF 15 mm f/2.8 Fisheye on Nodal Ninja 5 L. I have used the camera settings 53,5 for the lower rail and 79,5 for the upper rail (as suggested on the camera setting page). When I stitch the images in PTGui the stitch between the zenith image and the others are horrible. If i leave out the zenith image I get a good stitch.

    Does anyone have suggestions on what I should change in order to get it right. I have tried at least ten times with the same result.

    Best regards,

    Niklas
    I don't know what kind of scene your image set represents but...

    I shoot with a Nikon D40 and Nikkor 10.5mm FE. This combo gives 180 degree diagonal FOV fullframe FE images. I think your camera/lens combo may produce very similar images?

    When shooting outdoors I often had problems when stitching linking in the zenith shot (all sky).

    Instead of shooting 6 around at approx. -10 degrees and a zenith at +90 - which with my setup gives almost 360x180 coverage with small nadir 'hole' over NN5 rotator - Hans Nyberg suggested that I shoot 6 around at -10 and one up at +60. This gives similar coverage but almost always provides a good 'link' between horizon and sky and stitch usually goes without a hitch with automatic CP detection using Autopano Pro (my favourite stitcher).
  7. Re: Bad stitch of zenith

    #7
    Carel

    Hi Niklas,

    There is an issue with PTGUI v 7.7 and 7.8, where you get large errors when using PTGui as optimizer. At the Optimizer tab, bottom of page, switch "Optimize using PTGui" to "Optimize using Panorama Tools Optimizer" and you will have no problems. In case you dont have the Panorama Tools Optimizer, download Panotools12 from this page:
    http://photocreations.ca/panotools/index.html

    Cheers,

    Carel
  8. Re: Bad stitch of zenith

    #8

    Quote Originally Posted by Carel View Post
    Hi Niklas,

    There is an issue with PTGUI v 7.7 and 7.8, where you get large errors when using PTGui as optimizer. At the Optimizer tab, bottom of page, switch "Optimize using PTGui" to "Optimize using Panorama Tools Optimizer" and you will have no problems. In case you dont have the Panorama Tools Optimizer, download Panotools12 from this page:
    http://photocreations.ca/panotools/index.html

    Cheers,

    Carel
    Hey Carel,
    Welcome to the forum.
    This is great input. We've had others with similar issues and as you can image we were scratching our heads as things would line up for me ( I use the PTO option) but not for them.
    Thanks
    Bill
  9. Re: Bad stitch of zenith

    #9

    Another issue that can affect the stitching of the zenith is the orientation of the image. It is usual to present all the images to PTGui in the same orientation so that they have the same horizontal angle of view. Owing to the vagaries of auto rotation sensors in the camera, it is possible for bogus data to be provided when the camera is pointing vertically upwards. You may end up with a zenith image in portrait orientation, apparently just like all the others, but it could well be upside down. This matters because the lens optical axis is not usually accurately aligned with the centre of the image frame. Optimizing the shift parameters d & e compensates for this. Unfortunately, if the zenith image is upside down, then the shift parameters need to be the opposite of those for the other images. If the zenith is treated the same as the other images, you are likely to get stitching errors.

    There are four possible solutions to this problem:

    1. Turn off the auto rotation feature in the camera.
    2. Select individual lens parameters for the zenith (including the crop circle if appropriate).
    3. Check the metadata filed with the image in Photoshop. Ensure that all the images have the same orientation parameter (usually -90).
    4. Just inspect the zenith image and compare it with its neighbours for clues. The crop circle may be clearly in a different position, for example.

    Obviously, if the image is found to be upside down, rotate it in Photoshop. Despite being well aware of this problem, I have myself been caught out more than once. It really can make a big difference to the stitch.

    John
  10. Re: Bad stitch of zenith

    #10

    I second Carel in his observation.
    Something is broken in recent PTGui optimizers.

    I also recommend two-step workflow for assembling panos - first add images composing cylinder, then add zenith and (if necessary) nadir. Manual placement of CP's helps too. Individual lens parameters for zenith shot can be also useful.
  11. Re: Bad stitch of zenith

    #11
    JoshSommers

    I've run into similar problems with PTGui, but not just with the Nadir or Zenith. I have spent over an hour trying to get a 17 image pano to align in PTGui, only to give up and try the same images in Hugin and be done in about 15 minutes. Not bashing PTGui, but from my experience I have always had much better results with Hugin. Plus Hugin is about 50% faster for some reason. I have tried both optimization settings (PanoTools and PTGui) with similar results. These days, if I am doing a multi-row panorama, I always use Hugin, but if I am doing a single row panorama, particularly if I am doing a single row HDR pano, I will use PTGui because it does the HDR merging for me, and with single row panoramas, it seems to be able to align everything just fine.
  12. Re: Bad stitch of zenith

    #12

    Quote Originally Posted by JoshSommers View Post
    I have spent over an hour trying to get a 17 image pano to align in PTGui,
    It's difficult to guess why you should have so much trouble without knowing exactly what you did. I don't have any problems with two rows of 8 + N + Z using a Tokina 10-17mm fisheye at 14mm zoom. For all my panos, I generally use either a template to assign initial y,p,r values and lens parameters, or assign values manually making use of Fill Yaw and updating selected blocks of pitch values. The optimizer then gets off to a flying start and it's easy to get good alignment after deleting or amending any bad points.

    John
  13. Re: Bad stitch of zenith

    #13

    Quote Originally Posted by Carel View Post
    There is an issue with PTGUI v 7.7 and 7.8, where you get large errors when using PTGui as optimizer.[/url]
    I recently had an instance of this problem (or similar). After the PTGui optimizer produced a poor result, I tried PTOptimizer and that gave a good result. I then reoptimized with the PTGui optimizer, and that retained the good result. Whether or not the PTGui optimizer produced a poor result was affected by the starting position of the zenith image. I could find no evidence that this problem was confined to V7.7 and V7.8: V7.4 behaved just the same. I sent the project files that demonstrated the problem to Joost for investigation. He said he had received other reports and would investigate.

    John

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