I see the Entrance pupil position ( in front of image plane) listed for Otus at 101mm, and the 135 f2 APO at 34.5mm
Are these number sufficient for setting my panoramic nodal slider distance, or does one still need to do it manually by eye and iterations? Is the 101mm and 34.5mm suggested starting points, or are they exact, best distances to set?
Hi,
They are probably very accurate, if you can detect the image plane position accurate enough. A slight complication though, as poster 'elf' mentioned, the position of the entrance pupil may shift with focus. So it is always wise to do a verification of the initial setting, based on an actual shooting scenario.
Since most parallax occurs at close distances, I tend to calibrate my No-Parallax-Point (NPP) settings with the lens focused at something like 3 metres for landscape panos. I then place something (sometimes hang a wire with a weight from a lamp) much closer, and align it with something in the distance (a building or a lamp post somewhere outside my window), and use a very narrow aperture to get enough DOF to see features in both fore- and background. Then 2 shots (one rotated to the extreme left and another to the extreme right, just overlapping a few percent) are enough, although (if the lens has considerable distortion) also one in the middle may be needed to verify.
My TS-E 24mm II required NPP calibration with 0.5 mm accuracy in order to get parallax free results. Half a millimetre more or less produced a 1 pixel parallax in opposite directions. Most lenses require not more than a 1 mm NPP position accuracy.
Fish-eye lenses can shift their entrance pupil a lot with focus distance, luckily they can also be used with just a 'fixed' hyperfocal distance setting and cover from foreground to infinity, thus requiring just a single NPP to make a note of.
Cheers,
Bart