nadir & NN5

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  1. nadir & NN5

    #1

    Would it be possible to elongate the lower horizontal arm of NN5 approximately 6"?

    In order to photograph the nadir from exactly the same distance from the floor as other shots, one could shoot the horizontal shots, the zenith, then reverse the Vertical arm 180 degrees and extend it away from the tripod maximally while pointing the camera downward 90 degrees. One would have to move the tripod and center the lens over the nadir center point of course.

    Currently the lower horizontal arm is not long enough to achieve the desired results with this method.
  2. Re: nadir & NN5

    #2
    Users Country Flag
    Join Date: Apr 2008
    Location: Hong Kong
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    Quote Originally Posted by acer4x View Post
    Would it be possible to elongate the lower horizontal arm of NN5 approximately 6"?

    In order to photograph the nadir from exactly the same distance from the floor as other shots, one could shoot the horizontal shots, the zenith, then reverse the Vertical arm 180 degrees and extend it away from the tripod maximally while pointing the camera downward 90 degrees. One would have to move the tripod and center the lens over the nadir center point of course.

    Currently the lower horizontal arm is not long enough to achieve the desired results with this method.
    what lens are you using? if you limit the nadir hole to the size of the rotator, it should be easy to patch by your method. I don't think you need a longer rail.
    BTW, I am making a nadir adapter which will make it easier to turn the vertical by 180 deg.


    Nick



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  3. Re: nadir & NN5

    #3

    I am using the 10.5mm fisheye - it is almost doable but the tripod legs overlap a bit.
  4. Re: nadir & NN5

    #4

    Bringing this thread back to life, I've been doing some experiments and would like some suggestions please.
    (Historically I've manually bodged the nadir shot with cloning and so on)

    Latest tests with my Canon 5D and Tok 10-17 (at 12mm) have been 5 around at 0', zenith and then reversing the upper rail as per acer4x's comments.

    I've really struggled getting the nadir properly sorted with this so I can see two possible solutions.

    1 Reduce the nadir hole as per Nick's suggestion. - If so, what negative figure should I be looking at for the upper rail?
    2 Make use of PTGUI's viewpoint feature and tilt the upper rail down. - Doing this at about 45 - 60' doesn't seem to give me a good result when it comes to stitching.

    Thanks



  5. Re: nadir & NN5

    #5
    Users Country Flag
    Join Date: Sep 2009
    Location: Los Angeles, CA
    Posts: 348

    Nick has designed a swivel that works with the NN5 line. It allows you to swing the vertical arm 180 degrees out. You slide the tripod over and shoot your Nadir patch shot at the exact same height the original Nadir shot was taken. Using Alpha channel masks, you prepare your images to be stitched. No viewpoint technique required. When the production version appears on the web site, get one as quickly as you can. Follow this tutorial and your panoramas should stitch much easier with better results than the viewpoint correction. http://www.dlsphoto.net/Tutorials/NadirPatch2/index.htm
  6. Re: nadir & NN5

    #6

    Quote Originally Posted by DennisS View Post
    You slide the tripod over and shoot your Nadir patch shot at the exact same height the original Nadir shot was taken. Using Alpha channel masks, you prepare your images to be stitched. No viewpoint technique required.
    Assuming that the camera isn't exactly located at the original NPP after the tripod is shifted shifted sideways, viewpoint correction is still potentially useful for correcting any minor change in viewpoint.

    John
  7. Re: nadir & NN5

    #7
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    Join Date: Sep 2009
    Location: Los Angeles, CA
    Posts: 348

    I have not found that to be the case. The tripod can be off an inch or so and the images stitch just fine. The critical part is keeping the camera at the same height and level, which the swivel does. Tripod shadows are still a bear to deal with. I have needed up to 4 patch shots in order to remove all shadows from the Nadir. Maybe a big corporate logo would solve that problem? (Oh wait, that is a thread on another forum)

    Maybe a different use of the swivel would be to help get the offset viewpoint shot? Swivel the camera around (not necessarily 180), rotate the upper arm, take the shot. Better than hand held and you are not adjusting the camera on the upper arm.

    Do the other popular stitching software titles offer the option to auto generate points for only two selected images? I only have experience with PTGui, so I developed my workflow and pano head to optomize PTGui.

    Is PTGui the only one that offers viewpoint correction?
  8. Re: nadir & NN5

    #8

    Quote Originally Posted by DennisS View Post
    The critical part is keeping the camera at the same height and level, which the swivel does.
    If viewpoint correction is not available, optimizing the lens fov for the nadir shot will compensate for any difference in height. But if viewpoint correction iis available, then you might as well switch it on, no matter how much (or little) care is taken to position the camera exactly. For flat foors, I have found viewpoint correction works extremely well, and the camera position is not then particularly critical, though for a variety of reasons it is still often helpful to to take the nadir shot from a point reasonably close to the original NPP. The swivelling arm helps to facillitate this and is therefore a very welcome new feature.

    John
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