Archived posting to the Leica Users Group, 2004/07/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 4:26 PM -0500 7/1/04, Robert Palmieri wrote:
>Richard -
>
>At the considerable risk of pushing the wrong buttons with the "you're
>being unnecessarily fussy" types I'd like to pass along my personal
>experience with this issue.
>
>With my 50 'lux wide open it doesn't seem to be much of an problem
>(considering all the other conditions surrounding the usual shooting
>circumstances for this lens such as slow shutter speeds, etc.) I guess I
>don't really re-frame that far from center. With my 35 'cron (4th gen)
>I'm pretty sure this "focus then reframe" business does have a
>significant effect. Again, this lens isn't all that acute near the
>edges wide open so I've never really done a definitive test.
>
>I recall that some LUGger posted a compensation chart somewhere but I
>haven't found it yet. Perhaps someone with better recall (or more clever
>search keywords for the archives) might be of some help here...
>
>Bob Palmieri
Since most camera lenses, and especially high speed ones are not flat
field lenses, trying to compensate will prove futile. In fact, the
usual curvature of the object plane is concave as seen from the
camera, so there is some degree of compensation built into many
lenses and trying to calculate a compensation distance differential
trigonometrically will likely give you an incorrect result, besides
allowing your subject time to move to the next room and finish dinner
(which will require further compensation of various sorts).
--
* Henning J. Wulff
/|\ Wulff Photography & Design
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