In article
>In article <5c4986$kmp@newsstand.cit.cornell.edu>, d_ruether@hotmail.com (Bob
>Neuman) wrote:
[rest of post, on distortion checking, deleted...]
>> Focus shift with zooming is unfortunately common with Nikkor
>> zooms, and is sample-dependent. Since focus often shifts smoothly
>> more beyond infinity with zooming toward the short end of the
>> range, it is sometimes possible to add thin shims under the
>> lens bayonette to even out the focus (easier with MF and AF non-D
>> zooms than with AFD's, though, due to the presence of some wiring).
>By "focus shift with zooming," are you saying that if you focus, then
>recompose by zooming, that you may move out of focus (presumably,
>especially if zooming from shorter to longer focal lengths)? I would think
>this wouldn't be a problem under *most* circumstances (unless, for
>example, you needed to zoom in to focus on a certain object, then zoom out
>to compose), as long as you're using AF. The shimming seems like an
>unreasonable work-around, particularly for this AF-D lens.
Yes (which makes the oft'-heard advice to "zoom-in-to-focus-zoom-out-
to-shoot" pretty useless...) - but for both AF and MF, it is at worst
a minor annoyance (with single zoom/focus ring lenses). The shimming
can be very workable, if you are up for removing the lens bayonette
to add shims... (don't try it, unless you know how to remove the screws
without mashing the heads...;-).
>Very curious, since I'm seriously considering this lens. BTW, have you
>gotten your hands on it yet? I'd be interested in your take on the
>distortion issue.
I gather (this may be wrong) that the optics of the new 80-200mm f2.8
AF Nikkor are unchanged - if so, distortion is very moderate (and my
older version does not shift focus with zooming...). For hand-held
non-AF work (mostly what I use this lens for), I prefer the single
zoom/focus ring of the older version - though there sure are times
when I would like it to have a tripod socket...!).
Hope This Helps