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Empirical Notes on the Nikon 8-15mm and D850

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  • Empirical Notes on the Nikon 8-15mm and D850

    Over the last few years I have produced hundreds of panoramas using a Nikon 16mm f/2.8 lens on a D810 body:

    https://www.360cities.net/profile/johnwood

    This combination requires ten images - a row of six around, one up for the zenith, two pointing down, and one more for the nadir. The resulting panorama is 19,700 pixels wide. Nikon's D850 body has substantially higher pixel count and the 8-15mm fisheye is described as having much better resolution than the 16mm. This combination permits a panorama 17,000 pixels wide, made with half the number of shots, five instead of ten.

    Nodal Ninja's lens ring mount was used on R1 Ultimate tilt head pitched up at 7.5 degrees. The first task was finding the longest possible focal length that captured overlapped zenith shots plus down to the tripod legs. A long focal length is desired because that uses the most camera sensor area giving the highest pixel count in the finished image. I chose 13.1mm and wrapped 3mm wide vinyl tape around the lens to lock the zoom at that position.. The aperture range at this zoom position is f/4.2 to f/27. Next I shaved the lens hood pedals to eliminate vignetting. It is very nice to retain the lens hood and cap for transportation and storage and not have the front element unprotected.

    The fact that a fisheye lens does not have a fixed no parallax point has been widely discussed. I chose an empirical method to find the least parallax point. PTgui picks control points across the overlapping fields of view and ultimately determines the quality of the stitched image. Thus I made a series of panoramas, moving the lens along the rail in 5mm increments, then recorded maximum control point difference when stitched. It graphs as a U-shaped curve, beginning at 9 pixels at 20mm rail position, declining to 3 pixels at 30mm and back up to 24 pixels at 40mm. This was in a room with objects between one and five meters distant. I repeated the experiment outside with objects between five meters and infinity. As expected parallax was less apparent and I fine tuned the lens position to 28mm.

    This panorama, made at an aviation museum, has a maximum control point distance of 3.3 pixels:

    https://www.360cities.net/image/pro/...ighter-factory

    A particular advantage in this setup is making pole panoramas. The 16mm rig required raising and lowering the pole three times to change the pitch of the lens. One pole raise including a nadir shot works for the 8-15mm lens.
    Nikon 8-15mm with D850 on Nodal Ninja R1 Ultimate, Quick Mount and RD5 rotator.  Hyperlocal distance table wrapped around mount and wireless shutter release shown. Shaved hood left, stock hood right.
    Last edited by aviator; 04-29-2018, 05:38 PM.

  • #2
    Thanks for sharing the NPP. Wow, you shave the hood!
    Nick
    Fanotec
    We listen. We try harder.

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