pcacala@xxxxxxxxxxxxx writes:
<< I don't know. I presume that distance focusing aberration correction
(floating elements) keeps the image flatter than it otherwise might be
at infinity. But there are lots of other faults to correct and maybe
that isn't one of them. Curvature of field would be less important an
attribute to correct for when shooting 3D subjects, although one could
argue that at infinity it is very important. I think we can assume that
at the optimum magnification ratio, flatness of field is optimized. >>
An interesting comment on a pro photographer's website about this issue, was
that the depth of field of floating element lenses was often less than that
of conventional lenses: The defocussed image had different chromatic paths so
that chromatic component of bokeh affected circle of confusion even though at
the perfect focus the components came together. If this is true it adds
another dimension to focus offset.
Tim Hughes
>>Hi100@xxxxxxx<<
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