On Fri, Mar 29, 2002 at 08:53:08PM -0500, John A. Lind wrote:
> At 20:12 3/29/02, you wrote:
> >All 50mm non macro I have seen has barrel distortion, three 50/1.4 SC and
> >MC, 50/1.8 MC. 50/1.2, 55/1.2. May be I'm a bit exaggerated about the
> >distortion, but all the reports I have seen also shown about 1 0istortion.
> >For normal shooting it is fine, but for copy works, you need a very low
> >distortion lens unless you don't care about the quality.
> >
> >C.H.Ling
This are distortion values for Zuikos I have:
Zuiko 1.8/50 (#2746xxx) -1.0%
Zuiko 1.4/50 (882xxx) -1.0%
Zuiko 1.2/55 ('162xxx) -1.1%
Zuiko 3.5/50 (178xxx) -0.1%
Zuiko 2/85 (#123000) +0.7%
Zuiko 2.8/100 (#181xxx) +0.5%
Compared to other lens type`s all values are on the low-side.
>
> This should not imply the user "don't care about quality." If it's not
> detectable in *practical* use, it's as if the aberration doesn't exist. If
> you're seeking absolute perfection in actual lenses, you won't find it. I
> guarantee every one of your lenses has barrel or pincushion distortion,
> including the 50mm Macros. Non-debatable *fact*. Building a lens with
> having absolutely, exactly, "zero" or "none" is like trying to balance a
> needle on its point. It has not, cannot now, and never will
> happen. Variation in manufacturing guarantees it.
A lens-design with the elements located symetric to the apperture
would be 100 0istortion free. The Olympus 4/80 Macro does
look like a lens of this tye ( at least seem so, looking at the lens cutlaw)
Frieder Faig
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