I think this must be the patent of interest
<http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=23&f=G&l=50&co1=AND&d=PTXT&s1=coma.ABTX.&s2=olympus.ASNM.&OS=ABST/coma+AND+AN/olympus&RS=ABST/coma+AND+AN/olympus>
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Abstract
A large-aperture telephoto lens system with high telephoto ratio wherein
a negative thick meniscus lens is arranged in the rear lens group for
correcting the negative spherical aberration and negative coma which are
produced by the positive meniscus lenses with high refractive indices
positioned on the object side.
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The correcting element is described as a "moving" element which is used
to correct coma at close focusing distances. However, the lens
described is a 6 element lens and not the 5 element version depicted in
the eSIF. But there are at least 3 versions of this lens. Although the
depiction in the eSIF does not conform to the patent in number of or
shape of elements I could find no other patent to describe a different
design.
Chuck Norcutt
On 1/27/2013 10:54 PM, usher99@xxxxxxx wrote:
> Tendency towards symmetrical coma rather rings true at least at F2. I
> have not seen much of that discussed here lately though.
> I believe there is something in the patent to that effect as the lens
> appears to be an Oly modification of a Sonar type design with
> floating elements controlling aberrations at full aperture: in
> particular coma becomes more symmetrical helping to insure pleasing
> portraits at wide open aperture. I believe the Sonar type design if
> translated exactly led to focus shifts that Oly also ameliorated with
> the floating elements. I don't know about the claim at F4 though and
> the design did change a bit with the later MC version. Last outing
> used the OM Z 85/2 (AKA the "Queen's lens" in our house ala Jane Bown)
> though the bokeh can get edgy with busy background at 10 ft or so---had
> the CV90/3.5 (OM mount) in my pocket to use wide open for that
> circumstance though for people shots prefer the Zuiko at F2.8 if
> possible.
>
> Mike
>
>
>
>
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