Those shots look great Frank !
What is the problem with the 18/3.5 ?
...Wayne
-----Original Message-----
From: olympus
[mailto:olympus-bounces+wayne.harridge=structuregraphs.com@xxxxxxxxxxxxxxxxx]
On Behalf Of Frank
Sent: Wednesday, 18 March 2015 2:46 AM
To: usher99@xxxxxxx; Olympus Camera Discussion
Subject: Re: [OM] Complications in determining best digital home for OM Zuikos
I agree with Chuck.
Please look at these A7-Zuiko pictures (many with 21mm 3.5 and 35mm shift) of
Rotterdam and tell me why I shouldn't be happy with them.
Of course, modern lenses are generally better wide open and corrected, but also
often bigger and heavier. The performance of the Zuiko's is still nothing to be
ashamed of (I think). I do have an issue with my 18mm which I never noticed on
my Canon OM-6D, but hey, my keeper rate has dramatically increased with the A7.
Don't worry, be happy (with your Zuiko's)
<https://www.flickr.com/photos/78837261@N08/sets/72157648933246533/>
2015-03-17 1:05 GMT+01:00 Mike Gordon via olympus <olympus@xxxxxxxxxxxxxxxxx
>:
> I am very comfortable carrying my OM bodies and Canyon digital back
> but prefer to lug less heavy stuff these days.
> Thus my toe dip into MFT and possibly sony in the near future. I
> really like the new high performing lenses these days but miss some
> "rendering character" of my lenses built for film. Many newer ones are
> very sharp inded but tend to have a sameness about them and fair to
> middling bokeh---this is a vast generallization with some glaring
> exceptions. Perhaps the aspheric elements play a role. Anyway I enjoy
> the character and adapting of my old friends.
>
> I do not have a good handle on the complexities of determing how to
> achieve optimal performance. The adpater quality/precise dimensions
> seems to one variable. (Expense did not guarantee a good match for a
> lens in Roger's tests at lensrental)
>
> http://www.lensrentals.com/blog/2013/09/there-is-no-free-lunch-episode
> -763-lens-adapters This is not a trivial issue for wide angles and
> seems to be especially importnat for those with floating elements (may
> interact with sensor stack
> thickness) Minor offsets in thickness effect the peripheral rays in a
> nonlinear way and not corrected by depth of focus considerations. The
> corners just become lousy. Some lenses seem to developefield curavture.
> While the inherent amount of curvature in the optic will certainly
> vary from lens to lens, moving a given lens forward or rearward will
> have a non-linear (curvature is non-linear) relationship change
> between the distance to the center of the film plane vs. the distance to the
> corner.
> Shimming the adapter to get infiinty spot on corrects this. I don't
> understand this fully. Dr. Focus was skeptical of any serious issue.
> Another issue is the stack thickness already discussed and posted
> previously.
>
> http://www.lensrentals.com/blog/2015/01/a-thinner-sensor-stack
>
> There is now a commercial correction for this!! Some WA's as long as
> 28mm are affected.
>
> http://www.kolarivision.com/thinfilterconversion.html
>
> From Dr. Nasse at Zeiss--mostly an issue on tangential plane:
>
> From Nasse:
>
> "Lenses with a very large beam tilt react in a much more sensitive
> manner to a change of refractive index in the image space caused by
> filter plates in front of the sensor (such as low pass and IR-blocking
> filters). If the filter plate is not considered in the design of the
> lens, the edge definition will suffer. The effect of the additional
> path through the glass grows exponentially with the beam inclination.
> A Distagon which never achieves more than 20 beam tilt in the corner
> of the image reacts more tolerantly than a symmetrical wide- angle
> lens, which might reach a 45 tilt. This is why filters in digital
> Leicas are very thin to remain compatible with older optics. If the
> filter is significantly thicker, the contrast transfer for the image
> edge becomes worse for tangential structures. In the graph of the
> curves, this looks like the old retrofocus lenses but is caused by
> astigmatism rather than lateral chromatic aberration. The focus is
> shifted to greater distances for tangential structures by the
> additional path through the glass. If the best edge definition is to
> be achieved, then all that can be done is to stop down further."
>
> I wish I had a good handle on these issues.
>
> Adaptation bewilderment, Mike
>
>
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