wwp@yahoogroups.com:
Re: nodal point question
Thomas Mottl 2005-Mar-29 14:18:00
First of all, the Nodal Point is good to know for Macro photography but
nor for panoramas.
You are needing the Entrance Pupil Point.
This is the point of a Lens, measured from the film plane, where you
can rotate the whole system without getting parallax errors if it is
fixed above the rotating axis at this point.
As each lens has a different Entrance Pupil Point you must for each
lens/camera combo adjust it on your pano head.
Most Zoom lenses are having at every focal lenght a different Entrance
Pupil Point.
For Example the Entrance Pupil Point for a Sigma 15-30mm zoom is at
139.6mm at the wide and 129.7mm at the 30mm end. Always measured from
the film or sensor plane.
They also becoming negative when using large Tele lenses.
Hope it helps
Thomas