The subject of the referenced paper has to do with shooting panoramas
and validating that the "no-parallax" point of a lens is the "entrance
pupil" and not one of the "nodal points" as is frequently (and
incorrectly) stated. It also demonstrates that the aperture itself
determines the perspective of the image since changing the size or the
position of the aperture (while changing nothing else) can shift the
position of out-of-focus elements in the image.
From the standpoint of a single macro photo (vs a macro pano) I don't
think it has any bearing on your off-center aperture except that the
out-of-focus parts of the image would be slightly displaced from where
they would otherwise be. Nothing you could notice. However, I would be
concerned about the accuracy of the aperture and especially at small
openings. I don't know what would cause it.
Chuck Norcutt
Ken Norton wrote:
> I created a link to that article on the zone-10 site as I'm needing to
> digest it. But it does bring up something that I've been all concerned over.
>
> My 50/3.5 lens has an offset aperture. The aperture diaphrams are not
> centered in the optical path and are visibly out of alignment. I'd guess
> that it's off by the diameter of the opening at F11 or F16. My questions are
> two-fold:
>
> 1. Does it matter?
> 2. How difficult is it to fix?
>
> AG (bent out of shape) Schnozz
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