Need help - Len's not sharp at Infinity

Discussion in '35mm Cameras' started by Howie Axelrod, Apr 16, 2004.

  1. I use a Nikon zooms 28-70/f2.8 and 80-200/f2.8. They are sharp at
    short and mid range but not at infinity. Why?

    Also, since I am focused at infinity, does it matter as far as
    sharpness is concerned whether I shoot at f2.8 or f16? Any suggested
    f-stop at infity for maximum sharpness?

    Any answers to these questions would be appreciated.
     
    Howie Axelrod, Apr 16, 2004
    #1
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  2. Howie Axelrod

    Roger Guest

    Howie

    To a minor degree with these lenses, the f-stop setting does matter.
    However, a greater effect would be the use of a tripod.

    There are several things that can go wrong here, including the camera
    body, the correct focusing screen, the use of a tripod and the lens
    itself. However with this happening to two lenses of this quality I'd
    look at other factors as well as the lens.

    What camera body are you using?
    Are you auto focusing or manual focusing these lenses?
    Are you using a tripod?
    What is your shutter speed?

    Perhaps with some more information, we can begin to narrow this down.

    Regards,
    Roger
     
    Roger, Apr 16, 2004
    #2
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  3. Howie Axelrod

    ROBMURR Guest

    Yes it matters greatly whats in focus
    by the Fstops..F2.8 is very shallow
    depth of field. F8 to F16 would be
    much better for shots at infinity.
    Also focus on an object 1/3 of the
    way into the picture not just sticking
    the lens on the infinity setting.
    Yes it will look out of focus to you in
    the background, this is normal. hit your
    depth of field preview button to see what
    will be in sharp focus. That is how the
    picture will really look.
     
    ROBMURR, Apr 16, 2004
    #3
  4. Howie Axelrod

    Roger Guest


    After reading Rob's post, I see that there are multiple ways to
    interpret what you said. Are you saying that these lenses are not
    sharp at infinity when focused at infinity, or they are not sharp at
    infinity when focused at mid range?

    Howie, give us some more information.

    Roger
     
    Roger, Apr 16, 2004
    #4
  5. Howie Axelrod

    Bob Hickey Guest

    @ 28mm, you prolly won't even notice. If you shake the same @ 200mm, it will
    appear that nothing is sharp. It's not in either. Try it with the camera
    leaning on something solid. Bob Hickey
     
    Bob Hickey, Apr 16, 2004
    #5
  6. Quite ambiguous, indeed. Let's see...

    He stated that "Len's not sharp at Infinity".

    Makes me wonder if he's getting much of a picture of Len anyway, if that
    bloke is standing so far away. Or is Len standing at a shorter distance
    and he's trying to take pictures of him with the lens set to infinity?

    Ralf
     
    Ralf R. Radermacher, Apr 16, 2004
    #6
  7. Howie Axelrod

    columbotrek Guest

    Are you focusing with the focusing screen or auto focus or just lining
    up the OO mark? If what you are doing is lining up with the OO mark,
    then you could very well be out of focus at infinity with those lenses.
    Perhaps you noticed that they can be set a bit beyond OO. That is
    feature to compensate for variables in the design.

    Depth of field aside, Most lenses are sharpest in their mid apertures.
    This is especially apparent in the budget lenses.


    --
    "How can there possibly be liberty and justice for all, when, in the
    name of justice, people claim rights to income, food, housing,
    education, health care, transportation, ad infinitum? We can't. Positive
    rights to receive such things, absent an obligation to earn them, must
    violate others' liberty, by taking some of their income without their
    consent. They are really just wishes, convertible into benefits for some
    only by employing the government to violate others' rights not to have
    what is theirs taken." --Pepperdine Professor Gary Galles
     
    columbotrek, Apr 16, 2004
    #7
  8. Howie Axelrod

    Bandicoot Guest

    Oh dear, poor Len. I had a lens that happened to once, but never a Leonard.
    Maybe Len's ill?

    Sorry, can't resist a misplaced apostrophe! ;-)

    Others have already given you more helpful responses already, I see, and I
    tend to agree that if two lenses are affected, it sounds like either a
    camera problem (but that would affect other focus distances too) or one of
    steadiness.



    Peter
     
    Bandicoot, Apr 17, 2004
    #8
  9. Howie Axelrod

    TP Guest

    Maybe he's just blunt.
    Now see what you've started!

    ;-)
     
    TP, Apr 17, 2004
    #9
  10. Howie Axelrod

    Bandicoot Guest

     
    Bandicoot, Apr 17, 2004
    #10
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