<<I'm not sure I "get" this technique. Not only visually disorienting, but
highly
<<subjective and non-repeatable/comparable.
https://phillipreeve.net/blog/how-to-check-how-decentered-your-lens-is/
It is fast, easy and works well enough for the intended purpose. Fred on FM
devised a slightly modified version of this technique, but they all work about
the same. Decentering is a most common malady in wide fast lenses. Sigi seems
to have the best QA but about 1/3 of pixel peepers on FM have sent back a
14-24/2.8. Fred couldn't even find a centered copy of teh Sonnie 14/1.8 and
gave up. The Siggie at f2.8 is as good or better than the 14 prime.
<<<You tell me; can't you clearly see the differences, wide open, between these
highly rated and very similar lenses, including centering?
<http://www.moosemystic.net/Gallery/tech/Lenses/PanvsOly25mm/PanvsOly25mm.htm>
Nothing wrong with that methodology.
The Oly is decentered, BTW, with the left side being weak especially the left
lower. Oly tends to use designs less susceptible to small perturbations, so
they don't have too many lemons. Sigi appears to use more checks during
manufacturing to reduce sample variation an allow more tweaking. Roger from
lensrentals has said it is cheaper to replace a decentered lens than dissemble
and attempt to fix it. Whether they toss the returns or repackage them to less
fussy customers, I have no clue. Roger has also stated MFT lenses have more
sample variability than others.
I reprocessed the 7mm shots in DXO and cancelled the linear distortion
correction that cannot be avoided with ACR. I included a tad of deconvolution
sharpening. The lens looks centered, but soft in the corners. I had manually
focused with max mag with the chimney in the center of the frame. I bet it is
the field curvature doing the damage. I had hoped avoiding the distortion
correction would sharpen it up a bit as it avoid pixel torture. Moose had
previously posted the definitive treatise on the algorithms used for distortion
correction. I have never ever seen any more informative evaluation than this.
https://www.mlarchive.de/Olympus-OM/2016-09/msg00059.html
Here are the new images.
https://www.olyendomike.com/Oly-7-1428/i-98WZKTR/A
https://www.olyendomike.com/Oly-7-1428/i-hBvK8Lr/A
https://www.olyendomike.com/Oly-7-1428/i-m3xPPR8/A
https://www.olyendomike.com/Oly-7-1428/i-KWwQqB2/A
Too soft for me, Mike
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