Lens focusing scale

Discussion in '35mm Cameras and Accessories' started by Chan Tran, Jun 16, 2012.

  1. Chan Tran

    Chan Tran Member

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    I am wondering that the distance marking on the focusing ring on most SLR lenses are supposed to measure from film plane to subject or from front nodal plane to subject or what? None seems to really agree (they are close but not right on so can't say they are marked for one o another). Any information on this?
     
  2. E. von Hoegh

    E. von Hoegh Member

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    Film plane. On most older cameras, there was a marking to show the location of the film plane, it looks like a zero with a line through it.
     
  3. RalphLambrecht

    RalphLambrecht Subscriber

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    i thought, this was true for all camerasand filmbacks. it's true for allof mine, but all of mine are old!
     
  4. E. von Hoegh

    E. von Hoegh Member

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    Yeah, I don't recall seeing the marks on the few newer cameras I've handled.
     
  5. tkamiya

    tkamiya Member

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    I have the said mark on Nikon F100 and all of my digis (D200 and D60)

    I guess it's time for me to upgrade!
     
  6. Chan Tran

    Chan Tran Member

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    Thanks all! All my cameras have film plane mark and I knew about it. Just that my measured distance and what's on the focusing ring don't agree.
     
  7. semi-ambivalent

    semi-ambivalent Subscriber

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    On the Nikon F bodies the film plane was denoted by the "top" of the serial number on the rewind-side top cover. (Factoid, fer sure.)
     
  8. E. von Hoegh

    E. von Hoegh Member

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    I'd have to look, but I don't recall a mark on my F. I'll look in the instruction manual. The Nikkormat Ftn sitting here on the desk has the filmplane mark, though.
     
  9. Peltigera

    Peltigera Member

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    Suggests that someone has had the lens apart at sometime and failed to set infinity focus when reassembling. Or poorly manufactured.
     
  10. E. von Hoegh

    E. von Hoegh Member

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    Don't agree by how much? More than a few inches could be a problem at close distances.
     
  11. Chan Tran

    Chan Tran Member

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    Not by much! Setting the focusing ring at 2 m the actual distance to have the subject in focus is 1.9 so it's 5%. At close distance the scale is set at 0.5 m and actual distance is 0.48 it's 4%. That's for the Nikkor 50mm f/1.4 AI.
     
  12. Peltigera

    Peltigera Member

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    Seeing as the whole point of a SLR is that you focus through the lens, why does it matter? And unless you are shooting at f2 or bigger, won't the depth of field cover any inaccuracy if you are relying on measuring the focus for some reason?
     
  13. E. von Hoegh

    E. von Hoegh Member

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    That's true. I cannot think of many circumstances when you'd need to focus with a tapemeasure.
    The OP didn't say what camera it was, on an autofocus camera they're likely just ballpark figures.
     
  14. Chan Tran

    Chan Tran Member

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    what's the difference if I use an autofocus camera? The lens is a manual focus lens. For the measurement I used a Nikon FM because it has the split image. The reason I asked to question because out of curiousity a long time ago I made the measurement and remember that it's not accurate. Recently upon a D forum and some people used manual focus lenses on their mirrorless and can't focus with the D.. LCD so they resorted to the scale and found they are not accurate. I actually never used the scale on the SLR.