This is getting a bit creepy. Moose is being just a bit too agreeable
with the ol' Schnozz. Can we blame it on his recent trip in the
Turtle?
Now, to the diffraction issue...
Diffraction limiting may not be a hard limit, but it is the point
where the CoC has grown to the point where adjacent pixels are being
affected. But this doesn't take into consideration the resolution loss
due to the AA filter or the Bayer algorithm. The reality is that under
IDEAL conditions (black and white high contrast subjects with sharp
edged transitions) you are able to get to the limit of the sensor, but
in a color world the limits are much less and even under perfect
circumstances an 18mp sensor is able to resolve no greater than 4-5mp
in the reds and blues. Most colors involving 2-channel mixing top out
around 9mp. And that's not even considering the AA blurring. One other
thing to consider about CoC is that it is a gradual loss of contrast.
I have personally found that under most circumstances my real-life
resolution is about half of what the theoretical limits are. And most
importantly, a bit of pixel-sharpening in post is able to not only
erase some of the AA and Bayer blurring but will also address the
diffraction blurring while I'm at it.
Moose mentioned something about lenses. I've spouted off on this
before, so I won't reopen that wormy can, but will say thay my
PanaLeica lens is one of those lenses which definitely produces a
greater USABLE DoF than other lenses at the same focal length and
aperture. I know full well what the numbers say, but side-by-side
images tell a different story.
AG
--
Ken Norton
ken@xxxxxxxxxxx
http://www.zone-10.com
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