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Re: [OM] Lens/partial system/full system testing

Subject: Re: [OM] Lens/partial system/full system testing
From: "List, OM" <om-list@xxxxxxxxxxx>
Date: Thu, 9 Feb 2012 16:21:59 -0800
Convolution ... Deconvolution would be changing between frequency and
linear dimensions/ features. By measuring the frequency response of the
system you can adjust/improve the output without being concerned with the
individual parts of the system.
Jeff
On Feb 7, 2012 10:04 AM, "Moose" <olymoose@xxxxxxxxx> wrote:

> On 2/7/2012 8:47 AM, Chris Barker wrote:
> > Thanks for that appreciation, Moose, but what is deconvolution -- in
> layman's terms?  I've had a search on the Internet, but the explanations
> mean nothing to me.
>
> Non-scientific, possibly/probably therefore not entirely accurate, but
> indicative in a possibly useful way:
>
> When light is focused through a lens, the various imperfection in the lens
> convolute it, "intricately fold, twist, or coil"
>
> If the characteristics of the lens and the focal and image distances are
> mathematically defined, it is theoretically
> possible to un-fold, un-spindle and un-mutilate the resultant image into
> what it would have been if formed with a
> perfect lens.
>
> In practical terms, the lens can't be perfectly known and described in
> math, but the results of deconvolution may be
> startlingly good.
>
> At the level I'm talking about, with Focus Magic and other consumer tools,
> we have generic applications of deconvolution
> that make lots of simplifying assumptions about the lens that may have
> formed the image and allow specification of
> simple input(s) and choice of input criteria based on viewing a small
> sample of the image at 100%.
>
> Whilst far from the potential of custom tailored deconvolution, these
> simple versions still accomplish semi-magical
> transformations in many cases. FM, in this case, seems particularly suited
> to images from the S100, for whatever reasons
> of lens itself and sensor system. Oddly, this seems to be true across the
> zoom range.
>
> Deconvolution is rather processor intensive. My speculation was that
> someone, one of these days, will have an in-camera
> processor with the power to do custom, in-camera deconvolution specific to
> the lens, focal length and focal distance. I
> suspect the results will be spectacular.
>
> In the meantime, I suspect that some enterprising geek will eventually
> come up with a way to create lens profiles for
> any lens and read focal distance from EXIF to make the corrections in a
> post processing app.
>
> Looking at the corners of JPEG vs Raw files from the S100 in DPP, Canon's
> own Raw converter, I see some quite amazing
> corrections going on. Smeary, distorted stuff becomes clear. I don't think
> is is deconvolution, in the full sense, but
> I'm impressed. How do I work that into my work flow when corner details
> matters to me?
>
> Convoluted Post Moose
>
> --
> What if the Hokey Pokey *IS* what it's all about?
> --
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