RE: [Leica] how can the 75 Lux focus go bad? NOW - DOF

["Austin Franklin" <austin@darkroom.com>]

> Austin Franklin wrote:
> >Martin, as both Jim and I have pointed out, the film size is
> completely
> >irrelevant, and so is completely covering the film format.
> It is not an
> >assumption, it is a fact.  You are confusing optical DOF
> with printed DOF.
>
> Austin,
>
> Plane of focus is real.
> DOF is not real.
> The concept of DOF is based on an "acceptable circle of confusion" at
> various distances from the plane of focus.
> DOF is a generally agreed upon area around the plane of focus that
> produces an acceptable result to human eyes. There is no
> absolute DOF, it
> is an agreed upon value that most think gives a "good enough" result.

To say DOF is not real is absurd (not my first choice of words mind you).
DOF is real.  There may be no 'recognized standard' criteria for measuring
DOF, but it is measurable and is real.

> It may be that a definition or way of thinking that works for you is
> different from what works for others. But when you choose to operate
> outside of the accepted values you are on your own. Doing so and
> expecting others to buy into your new version of DOF is
> extraordinary.
<snip>
> Again, your ideas of "optical DOF" and "printed DOF" are your own.
> They are not part of any accepted explanation of the phenomena of our
> seeing something as in focus when it in fact is not.
>
> I think you have re-invented the wheel.
> And your wheel is not particularly round.

I did not make this up, I only provided an explanation, and a correct one at
that ;-)  If you don't understand the explanation, and/or the differences,
and/or don't want to, than that is your problem.  If you want to try to
understand it, then I am happy to oblige you.

One can always find some resource on the web to help reinforce ones
misunderstanding of almost any subject.  Just because it's referenced on the
web (or in a book for that matter) doesn't make it correct.