Digital BW, The Print

Austin, 

I'm very disappointed that this has degenerated to this name calling.
This forum is made for everyone to contribute information and learn
information -- its a two-way street.  The attitude that "I know everything"
has become "There is nothing that I need to learn".  How unfortunate!

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
> > > But they aren't different...they ARE both linear.  One is
> > merely part of an
> > > equation that represents the actual area of the opening...it's merely a
> > > representative number and could have been the actual area for
> > that matter!
> >
> > Are you really going to call that series of aperture numbers
> > and the shutter numbers, LINEAR??
> 
> Sigh.  I know exactly what linear means.  If you really believe I don't,
> then you obviously have a very low belief of my mathematical skills, and why
> are you even bothering discussing this?

I would have preferred to avoid personal attacks, but yes I do believe
your mathematical skills are a little rusty.  Why am I bothering?  Well,
two-fold, first I thought with a few nudges in the right direction, we collectively
could come up with useful model that might help some people communicate
better and help each other get "better" images.  Second, I saw what I
considered a lot of mathematical misinformation that was leading us all
down the wrong path.

There are those on the list who don't care a bit about the math, and frankly
I applaud them the most.  The most important thing about making pictures
IS actually making pictures, not measuring anything about them.  In the
final test the picture is "what you see", no more, no less.

> 
> I believe what would help you out a lot, is if you would try to understand
> what is meant.  Obviously a series of numbers 1, 2, 4, 8, 16, or 1, 1.4, 2,
> 2.8 etc are not linear.   I was not talking about the "series of aperture
> number" or the "series of shutter numbers", but what they represent IS a
> linear scale.  Their INDICATION, no matter what representational "set" of
> symbols you assign to them, is ONE f-stop, and f-stops ARE linear, whether
> they are shutter speed or aperture, as well as film speed.  Someone who
> would want to understand that (not misapply it and then claim it was wrong)
> would have understood that.
> 
> The shutter speed AND the aperture are exactly the same...one doubles/halves
> the speed of the shutter, and the other doubles/halves the AREA of the
> opening that allows the light in, and each doubling/halving is one
> f-stop...no matter what representation you assign to them.

Rethink some of this: every physical parameter you can measure in a lens
goes up/down exponentially as you go up or down f-stops.  That's means the
diameter of the opening, the area of the opening, the amount of light thru
the opening, and the amount of time that the shutter is open.  Notice also
the numbers used (f-numbers and shutter numbers) are actually reciprocals
of the physical parameters.  The beauty of an exponential series is that all
these math operations (square, square root, reciprocal) all maintain the
exponential character of the series.

In the last post you made some deal about AREA versus diameter, you seemed
to be saying that the diameter (f-number) went up linearly but the area
was the important number and that went up exponentially.  Well you take
a linear scale and square it (getting area) you get a quadratic series,
yet another different series.  Exponential series are the only ones that have
invariance with square, square root, reciprocal.

This high school math.  All of this can be seen in those texts.

> 
> And, again, this is ALL a red herring on your part, and merely confuses the
> issue...since none of this has anything to do with dynamic range.  

Well, you could probably spec and calculate DyR values to your heart's content
without understanding or caring anything about linear vs. exponential scales.
But if you then go and try to describe "what is all means" you darn
better know what the underlying stuff "means" before you try to explain
what the outside result "means".

Yes, the
> shutter speeds and apertures have a dynamic range, and they are NOT based on
> "1" as you erroneous claimed.  In a digital system, dynamic range is based
> on 1, if your digital representation is integer, but that is not necessarily
> true in an analog system...no matter what the representative symbols used
> within that system are.
> 
> Linear or exponential is ALSO not relevant to dynamic range, providing both
> the range and error are both in same "system".
> 
> > I can't imagine how a claim like that is helping your cause.
> 
> Roy, I don't have a "cause".  What I've said is merely fact, and I am simply
> trying to explain it to you, but you aren't getting it (or don't want to get
> it, for what ever reason), you are only looking for things to claim are
> wrong, that aren't wrong...and when I point out erroneous
> statements/understandings you make/have, you ignore them...  I completely
> understand what you are trying to claim, and as I've said, it is simply
> wrong.  It is a misunderstanding.  You can cite all the examples you
> want...but your misunderstanding is crystal clear to me.  I believe you are
> having trouble conceptualizing what the real meaning of dynamic range is,
> and obviously how it applies to imaging.  Dynamic range has a very important
> meaning/understanding, and it is not what you are claiming it is.  And, yes,
> it IS very misused and misunderstood, not only by your.
> 
> There is apparently no end to this that can be achieved, so it is foolish on
> my part to continue this, at least with respect to discussing this any
> further with you.  There is nothing new being added.  I don't really want to
> continue this off list, so I suggest we drop it.

I guess you're right about that.  I agree.  Let's drop it.

I might make one other little suggestion,  go talk to those people who
are "far smarter", ask them "how many steps of power" does that
stereo power amp have.  How big is a step.  The only spec you can
tell them is the dynamic range spec in the owner's manual.  

> 
> Austin

We should all get on with our life.

Good luck,
Roy