Quote Originally Posted by Mark Woods View Post
I think the discussion of front and rear nodal points refer to the center of the respective elements. The nodal point of the lens has to do with perspective and movement. We encounter this issue all the time in visual effects when shooting miniatures. The aperture can be placed in any number of positions determined by the lens designer. The vignetting caused by an aperture I would think relates to the image circle, and if the lens vignettes the image circle is too small for the format. I hope this helps. :-)
I'd beg to differ... each individual cell may have its own nodal points, but the entire system has a front and rear nodal point as well. And as Len noted, they can be outside the physical body of the lens on some designs, and inside on others. Regardless of the design or where the nodal points are, the correct pivot point should be the front entrace pupil at the optical axis.