Lens with Depth of Field indicator. (For full frame [36x24mm] digital camera.)

Discussion in 'Digital Photography' started by Henry, Dec 13, 2009.

  1. Henry

    Henry Guest

    Before I launch myself into the wonderful world
    of search engines, which I understand little of, I
    thought I would be better advised first of all, to
    start by asking those who may know more about
    digital cameras and lenses it than I do. Some of
    you may have used such lenses, assuming
    they exist!

    Thank you for your time.

    Henry.
     
    Henry, Dec 13, 2009
    #1
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  2. Henry

    ransley Guest

    Re: Lens with Depth of Field indicator. (For full frame [36x24mm]digital camera.)

    On Dec 13, 3:25 am, Henry <> wrote:
    > Before I launch myself into the wonderful world
    > of search engines, which I understand little of, I
    > thought I would be better advised first of all, to
    > start by asking those who may know more about
    > digital cameras and lenses it than I do. Some  of
    > you may have used such lenses, assuming
    > they exist!
    >
    > Thank you for your time.
    >
    > Henry.


    Maybe Zeiss
     
    ransley, Dec 13, 2009
    #2
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  3. Henry

    Ofnuts Guest

    Re: Lens with Depth of Field indicator. (For full frame [36x24mm]digital camera.)

    On 13/12/2009 10:25, Henry wrote:
    > Before I launch myself into the wonderful world
    > of search engines, which I understand little of, I
    > thought I would be better advised first of all, to
    > start by asking those who may know more about
    > digital cameras and lenses it than I do. Some of
    > you may have used such lenses, assuming
    > they exist!
    >
    > Thank you for your time.
    >
    > Henry.


    DoF depends on aperture, focal length, and sensor/film size. It is easy
    to put marks on a prime lens used only with a 24x36 sensor/film, but
    most digital era lenses are usable and used with various sensor sizes,
    and zoom lenses make it even more complicated.

    However, technological evolution outside the photography word allows one
    to evaluate the DoF using simple tools. There is a DoF calculator
    application for Java-capable phones (and likely one for iPhones).
    --
    Bertrand
     
    Ofnuts, Dec 13, 2009
    #3
  4. "Ofnuts" <> wrote in message news:4b252229$0$30363$...
    > On 13/12/2009 10:25, Henry wrote:


    >> Before I launch myself into the wonderful world
    >> of search engines, which I understand little of, I
    >> thought I would be better advised first of all, to
    >> start by asking those who may know more about
    >> digital cameras and lenses it than I do. Some of
    >> you may have used such lenses, assuming
    >> they exist!
    >> Henry.


    > DoF depends on aperture, focal length, and sensor/film size. It is easy to put marks on a prime lens used only with a 24x36
    > sensor/film, but most digital era lenses are usable and used with various sensor sizes, and zoom lenses make it even more
    > complicated.
    >
    > However, technological evolution outside the photography word allows one to evaluate the DoF using simple tools. There is a DoF
    > calculator application for Java-capable phones (and likely one for iPhones).
    > --
    > Bertrand


    I think there is more to consider for DOF than this --
    I've been an "unbeliever" when it comes to DOF scales...
    Notice that when they exist on lenses (or in charts), they
    symmetrically place on either side of the "correct" focus
    point at a given aperture both the nearer and farther focus
    points within which a selected range of "misfocus" supposedly
    is permissible before the image becomes visibly soft - or the
    distance range around the correct focus within which all is
    supposed to be "hunkey-dorey". Baloney!;-) OK, here's why.
    Imagine (or shoot) a landscape with a tree with leaves at a
    great distance. Include the same type of tree much closer to
    the camera. Now, using DOF scales and aperture, select the
    distance setting on the lens that the DOF scale says will just
    produce both good sharpness for both trees and also equal
    sharpness for both trees. Print the image. You may notice that
    the more distant tree that was photographed doesn't look as
    sharp as the nearer one. In fact, it may look down-right fuzzy
    in comparison! This is easy to explain. The "blob" size used as
    a standard for "sharp point rendition" is the same in both cases,
    but for the distant tree, the "blob" size represents a much
    larger proportion of its size, making it appear softer. Beware
    of this effect when including near-infinity landscape features.
    "Almost-sharp" horizons and distant features generally don't
    look very good, and you may need to "fudge" the focus a bit
    toward infinity-focus and also use a smaller stop than indicated
    by the DOF scales to really have good DOF coverage. BTW,
    I always considered that DOF indications cheated by about a
    stop..;-)
    --DR
     
    David Ruether, Dec 13, 2009
    #4
  5. Henry

    Better Info Guest

    On Sun, 13 Dec 2009 09:25:18 +0000, Henry <> wrote:

    >Before I launch myself into the wonderful world
    >of search engines, which I understand little of, I
    >thought I would be better advised first of all, to
    >start by asking those who may know more about
    >digital cameras and lenses it than I do. Some of
    >you may have used such lenses, assuming
    >they exist!
    >
    >Thank you for your time.
    >
    >Henry.


    Too bad you've saddled yourself with that SLR-design limitation. If you
    check into all the CHDK capable P&S cameras, you'll find that the on-screen
    EVF/LCD display (OSD) comes complete with all sorts of focal-distance and
    DOF information that you need.

    http://chdk.wikia.com/wiki/CHDK_User_Manual#DOF_Calculator

    Just a small example of what you can include (or not) in any location on
    your viewfinder's on-screen display (OSD) in any transparent colors of your
    choice. There's just no going back to the limitations of an optical
    viewfinder design once you find all that can be done with a good EVF/LCD
    viewfinder working in conjunction with superior super-zoom optics these
    days.
     
    Better Info, Dec 13, 2009
    #5
  6. Henry

    Ofnuts Guest

    Re: Lens with Depth of Field indicator. (For full frame [36x24mm]digital camera.)

    On 13/12/2009 20:59, David Ruether wrote:
    > "Ofnuts"<> wrote in message news:4b252229$0$30363$...
    >> On 13/12/2009 10:25, Henry wrote:

    >
    >>> Before I launch myself into the wonderful world
    >>> of search engines, which I understand little of, I
    >>> thought I would be better advised first of all, to
    >>> start by asking those who may know more about
    >>> digital cameras and lenses it than I do. Some of
    >>> you may have used such lenses, assuming
    >>> they exist!
    >>> Henry.

    >
    >> DoF depends on aperture, focal length, and sensor/film size. It is easy to put marks on a prime lens used only with a 24x36
    >> sensor/film, but most digital era lenses are usable and used with various sensor sizes, and zoom lenses make it even more
    >> complicated.
    >>
    >> However, technological evolution outside the photography word allows one to evaluate the DoF using simple tools. There is a DoF
    >> calculator application for Java-capable phones (and likely one for iPhones).
    >> --
    >> Bertrand

    >
    > I think there is more to consider for DOF than this --
    > I've been an "unbeliever" when it comes to DOF scales...
    > Notice that when they exist on lenses (or in charts), they
    > symmetrically place on either side of the "correct" focus
    > point at a given aperture both the nearer and farther focus
    > points within which a selected range of "misfocus" supposedly
    > is permissible before the image becomes visibly soft - or the
    > distance range around the correct focus within which all is
    > supposed to be "hunkey-dorey". Baloney!;-) OK, here's why.
    > Imagine (or shoot) a landscape with a tree with leaves at a
    > great distance. Include the same type of tree much closer to
    > the camera. Now, using DOF scales and aperture, select the
    > distance setting on the lens that the DOF scale says will just
    > produce both good sharpness for both trees and also equal
    > sharpness for both trees. Print the image. You may notice that
    > the more distant tree that was photographed doesn't look as
    > sharp as the nearer one. In fact, it may look down-right fuzzy
    > in comparison! This is easy to explain. The "blob" size used as
    > a standard for "sharp point rendition" is the same in both cases,
    > but for the distant tree, the "blob" size represents a much
    > larger proportion of its size, making it appear softer. Beware
    > of this effect when including near-infinity landscape features.
    > "Almost-sharp" horizons and distant features generally don't
    > look very good, and you may need to "fudge" the focus a bit
    > toward infinity-focus and also use a smaller stop than indicated
    > by the DOF scales to really have good DOF coverage. BTW,
    > I always considered that DOF indications cheated by about a
    > stop..;-)
    > --DR


    DOF is a subjective thing. DOF computation (and therefore lens marks) is
    based on a "circle of confusion" that is 1/1780 of the diagonal of the
    sensor/film(*), and this has been determined as the size of the smallest
    visible detail on the picture at normal viewing distance for most people
    (but there are people with eyes sharper than most).

    Btw, yes, DOF marks are symetrical, but the scale isn't linear. The fact
    that they are symetrical is nicely explained on Wikipedia IIRC.


    (*) this opens a whole can of worms if the image is meant to be cropped,
    which is a lot more frequent is digital times.
    --
    Bertrand
     
    Ofnuts, Dec 13, 2009
    #6
  7. Henry

    Henry Guest

    Thanks for the info folks.

    Henry.
     
    Henry, Dec 15, 2009
    #7
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