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Re: [OM] Diffraction, distraction, DOF

Subject: Re: [OM] Diffraction, distraction, DOF
From: Ken Norton <ken@xxxxxxxxxxx>
Date: Fri, 2 Mar 2012 17:34:39 -0600
I personally think that Dr. Diffraction is applying too much math to
the equation. It assumes a perfect sensor with no anti-aliasing
filtering and no bayer matrix. Those two factors alone will create a
dimmensional halving of the possible resolution. Sharpening methods
will bring back some of that.

But that last statement is where I start to part ways with Dr.
DIffraction on the calculations. The very same methods used to counter
the AA filter are going to apply just as effectively on the
diffraction blurring. Therefore, if we are regaining 50% of the
possible resolution thanks to pixel-sharpening, we are also regaining
50% of the possible resolution diminished by diffraction. (I'm pulling
50% out of my rump, so don't take it literally--each camera will be
different).

Furthermore, diffraction blurring isn't an all or nothing affair.
There is some penumbra to it, so it causes a decrease in contrast in
the pixel-level details before it will cause out and out blurring.

>From my own emperical evidence, I'm very comfortable with increasing
Dr. Diffraction's calculations by a full stop.

Even so, it still comes down to final output. DoF and diffraction
calculations vary entirely on output resolution, size and viewing
distance.

Dr. Alternate Reality

AG

-- 
Ken Norton
ken@xxxxxxxxxxx
http://www.zone-10.com
-- 
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