Your stitching problems are almost certainly due to parallax. While you would normally set up the camera such that it rotated about the entrance pupil of the lens to avoid the effects of parallax, it's a sad fact that for a fisheye lens the apparent position of the entrance pupil varies according to the varying angles of the light rays entering the lens. Light rays from the nadir area are entering at angles approaching 90 degrees to the lens axis. For these rays, the entrance pupil is close to the front surface of the lens, whereas for rays coming from the horizontal level, the entrance pupil is much further back into the lens. The optimum position for the camera must therefore be a compromise. You might try shifting the camera back a little so as to give priority to the nadir area which is nearest to the camera and therefore more likely to be visibly affected by parallax errors.
Another possible cause of trouble with the zenith and nadir images is that they might be in different orientations to that of the horizontal row images. You should have all the images in the same orientation: all in landscape or all in portrait. But more than this, images can be in one of 4 possible orientations obtained by rotating the image in increments of 90 degrees. The zenith and/or the nadir images might be upside down relative to the other images owing to the orientation sensor in the camera giving arbitrary data when the camera points directly up or down due to gravity acting at right angles to the image sensor. It's important that all the images are in exactly the same orientation because of the way the global lens shift parameters are applied to correct for the lens axis not being exactly aligned with the centre of the image sensor. If you can make available the set of images (half size jpegs of the ev0 set would be good enough), more specific help might be possible. John > > -- A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ --- You received this message because you are subscribed to the Google Groups "hugin and other free panoramic software" group. To unsubscribe from this group and stop receiving emails from it, send an email to hugin-ptx+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/hugin-ptx/1e1ad399-ca01-41f9-a4f7-9ed3b449505c%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
