landscape mode focusing problems

Discussion in 'Digital Photography' started by Ben Thomas, Dec 2, 2003.

  1. Ben Thomas

    Ben Thomas Guest

    Hi all,

    I've tried using the landscape mode of my Kodak DX6490 camera, which to the best
    of my knowledge means it should go into an infinite focus mode and the horizon
    should be in focus no matter what.

    I've managed to take some photos where the horizon is well out of focus and some
    objects within a kilometre are in focus. If I half depress the shutter release
    button, the camera attempts to focus the image, but I would have thought it
    doesn't need to do that.

    What exactly should be happening when I use landscape mode? Is there a way to
    calculate what will be in focus based on aperture settings when using the
    landscape mode and would that be any different to depth of field calcs when not
    using landscape mode? I've played with some depth of field calculators, but when
    the focus brackets dissappear in landscape mode it's hard to force the camera to
    focus on what I want to use as the near focal point.

    Thanks for any advice.

    --
    Ben Thomas - Software Engineer - UNICO Computer Systems
    Melbourne, Australia

    Opinions, conclusions, and other information in this message that do not
    relate to the official business of my employer, UNICO Computer Systems,
    shall be understood as neither given nor endorsed by it.
     
    Ben Thomas, Dec 2, 2003
    #1
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  2. Ben Thomas

    DHB Guest

    Ben,
    can't speak specifically about how Kodak implements this mode but I
    can tell you how some other companies do so, like Sony & Canon.

    The modes such as "close-up", "portrait" & "landscape" just limit the
    focus range of the auto focus system based on the expected average distance.
    So if you have it set to "landscape" it's not forcing a preset infinity
    focus but rather just telling the auto focus not to bother trying to focus
    closer than X distance away. This generally makes the auto focus system
    quicker & more accurate which can also prevent the focus from moving from 1
    extreme to the other "hunting" for a focus lock.

    My Sony digital video camera has this feature & if I am video taping
    something through a window it might focus on the window instead of what I
    want it to focus on some distance beyond the window. Thus selecting
    "landscape" prevents the camera's auto focus from even looking that close
    thereby prevents this extremely unfocused problem completely.

    If your shooting in very low light or at a low contrasted scene,
    consider using manual focus if your camera has that feature. Hope this
    helps, camera manuals are often somewhat misleading or poorly explain this
    camera function so don't feel like you missed something, you may not have.
    I learned this the hard way by trial & error but the effect is far easier to
    see with a video camera but the principle is the same for most digital still
    cameras.

    Respectfully, DHB
     
    DHB, Dec 2, 2003
    #2
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  3. Ben Thomas

    Ben Thomas Guest


    Thanks for the advice. Any idea what X (your symbol above) is for Sony and Canon
    cameras?

    --
    --
    Ben Thomas - Software Engineer - UNICO Computer Systems
    Melbourne, Australia

    Opinions, conclusions, and other information in this message that do not
    relate to the official business of my employer, UNICO Computer Systems,
    shall be understood as neither given nor endorsed by it.
     
    Ben Thomas, Dec 3, 2003
    #3
  4. Ben Thomas

    DHB Guest

    Ben,
    "X" is a place holder for a numeric variable, in this case a
    distance preset by the camera manufacturer. This value is sometimes stated
    in the manual & sometimes not. To give you an example:

    My Canon A40 manual (pg. 55) states the following:

    Macro Mode: "(6.3 in. to 2.5 ft.) from the lens tip when at maximum wide
    angle and in the range of (10.2in. to 2.5 ft.) when at the maximum telephoto
    setting."

    So here they quote 4 "X's" or 2 ranges of "X".

    Snapshot Mode: "Use this mode to record subjects in the range of (4.9 to 8.2
    ft.)."

    Infinity Mode: "Use this mode to record landscapes and distant objects.
    It can also be used for compositions combining both near and distant
    objects."

    Talk about an ambiguous Infinity Mode description! Sadly the same
    wording is used in the manuals for my Canon S300 & S330 as well. The main
    point is that your manual may or may not provide a useful explanation of
    your camera's Infinity Mode just as mine leaves enough room for speculation
    to drive a truck though it. If your manual does not tell you & you really
    must know, than the measured trial & error method done in good light with a
    high contrast object may be the only way to learn it's closest focus point
    in that mode & remember that it will change if you zoom in at all.

    Just knowing that there is a range & not a fixed "Infinity Focus" should
    help you to work with your camera & not against it. Wish I could give you
    more information but trial & error testing may be you best option or if your
    very lucky a nicely written e-mail to tech support for your camera's
    manufacturer might yield additional useful information but the latter is
    likely a long shot but still worth a try.

    Best of luck & if your camera has manual focus, that is likely the
    easiest way to deal with this but be warned that most cameras can & need to
    be able to focus past "infinity focus" so to get the sharpest pictures start
    with manual full "infinity focus" but also take a few pictures just slightly
    short of infinity as these may be the best focused.

    Respectfully, DHB
     
    DHB, Dec 3, 2003
    #4
  5. Ben Thomas

    Ben Thomas Guest

    My manual is similarly vague, and in my opinion does not describe what the
    camera does.

    "Use the landscape setting to gain maximum sharpness of far away scenes."
    "With this setting, the camera uses a fixed, infinite focus. Framing marks are
    not available in lanscape mode."

    The focus is definitely not fixed in landscape mode.

    In close-up mode the manual describes the vocal range for wide-angle and
    tele-photo shooting, but it doesn't do the same for landscape. Bummer.

    Thanks again for your help.





    --
    --
    Ben Thomas - Software Engineer - UNICO Computer Systems
    Melbourne, Australia

    Opinions, conclusions, and other information in this message that do not
    relate to the official business of my employer, UNICO Computer Systems,
    shall be understood as neither given nor endorsed by it.
     
    Ben Thomas, Dec 3, 2003
    #5
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