On Tue, Apr 7, 2009 at 9:17 AM, JC OConnell <hifis...@gate.net> wrote:

> I dont agree with that terminology, it's his not mine.
> DOF is relative sharpness of foreground and background
> objects in an image compared to the objects in the plane
> of focus. ( just my working terminology FWIW).

So, if a certain object in the foreground is half as sharp (or twice
as blurred) as an object in the plane of focus, is it within the DOF?
What if it's a third as sharp?  A quarter?  Where do you draw the
line?

To define the DOF, you need a concept of "acceptable sharpness" or
"acceptable circle of confusion".  These criteria typically arise from
assumptions about the final print (film size, print size, viewing
distance...).  In our previous discussion, I provided a number of
reputable citations discussing the origin of these criteria.  If you
had read them, instead of screaming unsubstantiated assertions back at
me, we wouldn't have to go through this again.

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