focus problem with Nikkor 35-70 at 4-6 feet...ish

Discussion in 'Digital SLR' started by Angus Manwaring, May 17, 2005.

  1. Hi all,

    Maybe its me, but I really don't think so. I'm using a Nikkor 35-70 zoom
    (f2.8) with a D1x and I have had a recurring problem with focus under
    certain conditions.

    I decided to try a little test exercise this afternoon, and took several
    oblique shots of a pen placed at various distances on a rubber mat with a
    grid design on it.

    It was easy to focus and I'm not sure what I hoped to prove, but while the
    other shots were fine, the shot of the pen at 5 feet was way out of focus.
    It is definitely a focus issue, I used flash, on a tripod, with the lens
    wide open. You can see the strap of my camera bag about foot further away,
    pin sharp! I used the lens fully zoomed in for the test, but zoomed in and
    out fully between each shot. Zooming in and out fully with the lens is not
    a very graceful procedure as there is a surprising "bump" when you reach
    the limits at either end of the zoom.....

    Any thoughts?

    I'm completely capable of making mistakes, but I've had similar results at
    this sort of distance a number of times, and I had all the time in the
    world (and ideal conditions) to focus during the test. :-/








    All the best,
    Angus Manwaring. (for e-mail remove ANTISPEM)
     
    Angus Manwaring, May 17, 2005
    #1
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  2. Angus Manwaring

    Alan Browne Guest

    It sounds like you have a problem. For what it's worth, I too had
    trouble testing this on the Maxxum 7D, but once I found a good test
    procuedure and setup, it proved to be okay.

    Basically
    ...I printed a grid on my printer.
    ...Found a way to lay it very flat on a flat substrate. (clamps)
    ...Placed a constrasty metal post (an inch high) with the near edge of it
    tangential to the '0' (focus plane)
    ...lit it well, so I could see what I was doing
    ...shot at fairly sharp obliques.

    and took my test shots, MF and AF. No problem.

    Cheers,
    Alan
     
    Alan Browne, May 17, 2005
    #2
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  3. Angus Manwaring

    andrew29 Guest

    OK. Can you let us see this picture? I think I know what might be
    happening, but need to see it.

    Andrew.
     
    andrew29, May 18, 2005
    #3
  4. On 18-May-05 09:43:12, andrew29 said

    Its a bit tricky for me to organise that Andrew - I don't have internet
    access at work.... and the image is currently on a computer that doesn't
    belong to me.

    Can you give me any clues?

    Many thanks for your interest.


    All the best,
    Angus Manwaring. (for e-mail remove ANTISPEM)

    I need your memories for the Amiga Games Database: A collection of Amiga
    Game reviews by Amiga players http://www.angusm.demon.co.uk/AGDB/AGDB.html
     
    Angus Manwaring, May 18, 2005
    #4
  5. Angus Manwaring

    Andrew Haley Guest

    My gess is that your camera focussed on a strong contrast subject just
    outside the area marked as the focus sensor. Either that, or perhaps
    a little movement after focussing?

    Andrew.
     
    Andrew Haley, May 25, 2005
    #5
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