I love it when you guys talk dirty.
Nathan Wajsman
Alicante, Spain
http://www.frozenlight.eu
http://www.greatpix.eu
PICTURE OF THE WEEK: http://www.fotocycle.dk/paws
Blog: http://nathansmusings.wordpress.com/
YNWA
On Aug 26, 2013, at 5:15 AM, usher99@xxxxxxx wrote:
> P. S. Moose writes:
>
>> Mike G and others have pointed out that in theory, DC should not work
> for
>> correcting diffraction blur. In practice, with
>> my lenses and images, it increases detail visibility and 'sharpness'
> in images
>> as apertures small enough that folks like
>> Chuck say they are diffraction limited.
>
> No, no. Chagrined Mike made a 140 deg turn in a rather long Feb post.
>
> http://lists.tako.de/html/Olympus-OM/2013-05/msg02068.html
>
>
> Yes, empirically R-L deconvolution can improve diffraction softened
> images. However, there is a rather hard high freq cut off with
> diffraction unlike
> a Gaussian blur where high freq info leaks into the image. Why DC
> still works is well, convoluted--- but detail contrast is improved even
> if no/little actual resolution derived.
>
> My current conjecture is DXO uses non PSF deconvolution but applied
> in a weighted fashion in the image where the lens is most affected by
> aberrations--at least
> as far as that one function. That opinion is based on a few
> correspondences with their tech support a number of years ago--they
> keep their cards
> very close to their chest now. I have read that Canyon with DLO
> actually mathematically models the lenses including diffraction
> effects and the AA filter.
>
> I agree with Moose that lightly applied deconvolution is less
> manipulative than USM as it is recovering data contained within the
> image.
>
> Perhaps not always quite sharp enough, Mike
>
>
>
>
>
>
>
> --
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