Re: I Miss my Viewfinder !

Discussion in 'Digital Photography' started by Whisky-dave, May 31, 2011.

  1. Whisky-dave

    Whisky-dave Guest

    On May 28, 12:37 am, Eric Stevens <> wrote:
    > On Fri, 27 May 2011 13:42:34 +0200, Mxsmanic <>
    > wrote:
    >
    > >Eric Stevens writes:

    >
    > >> Why is not a two-dimensional picture of a three-dimensional tree just
    > >> a symbol?

    >
    > >Because it models the tree. It directly shows the shape of the tree, anddoes
    > >not require reference to a third source of information.

    >
    > >A symbol is just an index into a database, and the database contains the
    > >representation.

    >
    > >Digital systems use symbols, analog systems use models.

    >
    > I wonder if the ancient Egyptians knew that.


    Well they knew about pi which is an analogue number but needs to be
    divided
    digitally to be used.
     
    Whisky-dave, May 31, 2011
    #1
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  2. Whisky-dave

    Whisky-dave Guest

    On May 31, 11:00 pm, Eric Stevens <> wrote:
    > On Tue, 31 May 2011 06:03:32 -0700 (PDT), Whisky-dave
    >


    >
    > <> wrote:
    > >On May 28, 12:37 am, Eric Stevens <> wrote:
    > >> On Fri, 27 May 2011 13:42:34 +0200, Mxsmanic <>
    > >> wrote:

    >
    > >> >Eric Stevens writes:

    >
    > >> >> Why is not a two-dimensional picture of a three-dimensional tree just
    > >> >> a symbol?

    >
    > >> >Because it models the tree. It directly shows the shape of the tree, and does
    > >> >not require reference to a third source of information.

    >
    > >> >A symbol is just an index into a database, and the database contains the
    > >> >representation.

    >
    > >> >Digital systems use symbols, analog systems use models.

    >
    > >> I wonder if the ancient Egyptians knew that.

    >
    > >Well they knew about pi which is an analogue number but needs to be
    > >divided
    > >digitally to be used.

    >
    > They didn't actually know about pi in the modern sense.

    They didn;t need to as the errors from not knowing weren't
    significant.

    >They did know
    > about a method used to approximate pi when determining the area of a
    > circle. This equated pi to 256/81 which is fairly close.


    So a digital value rather than the analogue value.

    The thing about digital is it's accurate for humans and is much more
    useful
    for humans than an analogue system in most cases, in fact we use
    digital far more than analogue.
    You might say lets meet after breakfast but the best approach is
    digital we'll meat at 10am.
    Which is more accurate .......


    >You should
    > look up the Rhind or A’h-mosè Papyrus.
    >
    > Regards,
    >
    > Eric Stevens
     
    Whisky-dave, Jun 1, 2011
    #2
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  3. Whisky-dave

    Whisky-dave Guest

    On Jun 1, 5:46 am, Mxsmanic <> wrote:
    > Whisky-dave writes:
    > > Well they knew about pi which is an analogue number but needs to be
    > > divided digitally to be used.

    >
    > There's no such thing as analog or digital numbers.
    >
    > Pi is a transcendental, and thus irrational, number. It cannot be represented
    > digitally. But it is neither analog nor digital in itself.


    If you want to use the number then you use it digitally if it's in a
    formula
    it's analogue.
    If you know what pi is then you can use it.
     
    Whisky-dave, Jun 1, 2011
    #3
  4. Whisky-dave

    Whisky-dave Guest

    On Jun 1, 10:49 pm, Mxsmanic <> wrote:
    > Whisky-dave writes:
    > > If you want to use the number then you use it digitally if it's in a
    > > formula it's analogue.  

    >
    > Actually, equations and formulae are normally digital.


    No they are analogue, we used to have analogue computers here but
    digital was more accurate
    for the majority of computation.

    > For example, 2/3 is a
    > digital representation, not analog. So is 0.66666. The only time you come
    > across analog representations is in domains like geometry, where you might
    > choose to represent something with a drawing. Drawing a circle is analog;
    > giving the equation for a circle is digital.


    So describe this circle to me, can you describe it only use analogue
    terminology.

    >
    > To represent pi digitally, you can simply say circumference / diameter.

    No that's analogue.

    >You
    > can represent it digitally with a decimal equivalent (3.14159265358 ...),but
    > the number of digits required is infinite, so it can't be exact.


    If it's infinte then an analogue answer will NEVER be correct .

    > You can
    > represent it in analog form by cutting a circular chunk of wood of a given
    > diameter, then measuring the circumference.


    Yes but what is this given diameter ?
     
    Whisky-dave, Jun 2, 2011
    #4
  5. Whisky-dave

    Whisky-dave Guest

    On Jun 2, 3:58 pm, Mxsmanic <> wrote:
    > Whisky-dave writes:
    > > No they are analogue, we used to have analogue computers here but
    > > digital was more accurate for the majority of computation.

    >
    > Show me an example of an analog equation.


    How about E=MC2
    How about differentiation and calculus


    > > So describe this circle to me, can you describe it only use analogue
    > > terminology.

    >
    > There's no such thing as analog terminology. Analog means a model, not a
    > description. Descriptions are digital.


    So what size is this circle ?

    >
    > > No that's analogue.

    >
    > Where's the model in circumference / diameter?


    You tell me it's your circle.


    >
    > > If it's infinte then an analogue answer will NEVER be correct .

    >
    > Sure it will. The circumference of a circular object is exactly pi times the
    > diameter. In fact, it cannot be anything else.


    So how does that tell you the diameter.


    > > Yes but what is this given diameter ?

    >
    > It doesn't matter. Whatever the diameter, the circumference will be exactly pi
    > times that diameter.


    So calculate it tell me what the result is .
    So tell me what the circumference of a circle is.
     
    Whisky-dave, Jun 2, 2011
    #5
  6. Mxsmanic <> wrote:
    > Eric Stevens writes:


    >> Yes it can. Consider the geomtry of a spherical surface or,
    >> alternatively, a pseudosphere.


    > A circle is two-dimensional.


    So is a shadow.

    >> Only on a plane surface.


    > Two dimensions can't be anything else.


    A shadow can fall on 3d terrain.

    -Wolfgang
     
    Wolfgang Weisselberg, Jun 4, 2011
    #6
  7. > Mxsmanic <> wrote:
    [Let's snip context like you do]

    > Only if there's a third dimension. Visit Flatland sometime.


    I don't want to visit you, you're too two-dimensional.

    PS: Digitizing and printing works better than analog enlargement:
    http://clarkvision.com/articles/digital_advantage/index.html

    -Wolfgang
     
    Wolfgang Weisselberg, Jun 5, 2011
    #7
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