Nikon D70s out of focus

Discussion in 'Nikon' started by AlexE, Dec 8, 2007.

  1. AlexE

    AlexE Guest

    Hi
    I have a D70s and a Nikon 18-200 lens. When the lens is at the wide
    angle end (most notably 18 mm) the camera focuses at about 2 or 3
    meters. Thus anything in the distance will be slightly blurred, at least
    when viewed full size. I always have to zoom to 200 mm and focus and
    then bring it back to 18. Is this normal? It is inconvenient at the very
    least.
    TIA
    Alex
     
    AlexE, Dec 8, 2007
    #1
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  2. AlexE

    C J Campbell Guest

    It is not normal. Something is wrong with your autofocus.
     
    C J Campbell, Dec 8, 2007
    #2
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  3. AlexE

    AlexE Guest


    Goddamn right something's wrong. Same thing with the original lens 18-70
    mm. :(
     
    AlexE, Dec 8, 2007
    #3
  4. AlexE

    Frank Arthur Guest

    And of course you sent the camera & lens to Nikon's Service Dept. to
    check it out?
     
    Frank Arthur, Dec 8, 2007
    #4
  5. Yes, that is called Depth of Field and depending upon how you want to design
    your photos it can be very desirable or a curse. If you want to have both,
    the foreground at 2m and the background in the distance, in focus then you
    need to use a small apperture like maybe f16 or f22.

    jue
     
    Jürgen Exner, Dec 8, 2007
    #5
  6. AlexE

    me Guest

    Gotta love folks who post these type of questions, providing absolutely
    zero in regard to the camera settings, nor pointing to any image containing
    full exif data. I guess we're supposed to be clairvoyant?

    First, question. the camera AF Area Mode isn't set to Closest Subject by
    any chance is it?
     
    me, Dec 8, 2007
    #6
  7. AlexE

    Colin_D Guest

    Well, in contrast to the other posters, I think your lens is quite
    normal. I am a Canon man, and my main lens is a 17 - 85 mm, not quite
    the same range as your 18 - 200, and it exhibits a similar scale error
    between wide angle and the long end.

    The reason is that is extremely difficult designwise to arrange the
    scale to be accurate over the zoom range, and since focusing is
    predominantly automatic, it doesn't really matter. Unlike older,
    especially non-zoom lenses, precise scaling on slr camera lenses with AF
    is neither achievable nor necessary. It is at best an indicator only,
    not to be relied on to focus by if you want precise focus.

    One thing that *is* wrong is your focusing at full zoom and then zooming
    back to your required length. This is because zoom lenses are not
    designed to maintain focus while zooming, so focusing at the intended
    zoom setting is necessary - which your AF does. If you focus at full
    zoom and then zoom back you can practically guarantee an out-of-focus
    picture. I say 'practically' because DoF can mask small degrees of
    misfocus - but if you shoot wide open you will soon see the difference.

    Colin D.
     
    Colin_D, Dec 9, 2007
    #7
  8. AlexE

    Tony Polson Guest


    On the contrary, a true zoom lens *will* maintain correct focus
    throughout the zoom range. A lens that does not do this is correctly
    termed "varifocal".

    My SMC Pentax-A 35-105mm f/3.5 (constant) manual focus lens is
    varifocal. The focus varies significantly throughout the zoom range.
    It doesn't matter too much because it's a one-touch lens, with a
    combined zoom/focus ring, but the change in focus is fairly dramatic.

    But there are benefits - optically, the lens is a fine performer. The
    combination of excellent sharpness and smooth bokeh would have been
    almost impossible to obtain in a true zoom of the same focal length
    range and maximum aperture.
     
    Tony Polson, Dec 9, 2007
    #8
  9. AlexE

    Buy_Sell Guest

    Buy_Sell, Dec 9, 2007
    #9
  10. The term you are looking for is "parfocal".
    Every lens that changes focus length is commonly called "zoom",
    and even the action of changing the focus length is often called
    "zooming". Then there are "18x super zoom" cameras.

    -Wolfgang
     
    Wolfgang Weisselberg, Dec 10, 2007
    #10
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