Needed something to do this weekend.
When taking a hand held Nadir patch shot, the more accurately you can point the camera at the pivot point on the ground directly below the center of your tripod or monopod the easier it is to stitch in the Nadir patch shot.
I mounted a laser pointer onto my D800. The red dot is calibrated to point to the exact center of the picture. Now I can easily take an accurate offset hand held Nadir patch shot. I just need to remember to remove the bright red dot from the center of the patch shot prior to stitching.
I did the same thing for my NEX7/Sigma 8mm rig. Having a laser pointer sure makes stitching easier.