Difference between lenses (Nikon)

Discussion in 'Nikon' started by Sheldon, Feb 4, 2005.

  1. Sheldon

    Sheldon Guest

    Well, the G version (the cheap one) has a plastic mount. That scares me.
    Sheldon, Feb 7, 2005
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  2. Sheldon

    Ken Tough Guest

    Yeah, but the reason I wanted f4.5+ is so that it would be lighter.
    If I'm hiking or travelling, I don't really want to haul around a
    kilogram(s) monster.
    Too bad; some of Canon's IS offerings aren't too expensive, at least
    not all in the $1000+ range of f2.8 zooms.
    Ken Tough, Feb 7, 2005
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  3. Sheldon

    paul Guest

    Does it not meter at all or is simply 'off'? There must be some kind of
    reading coming through & it seems you could adjust the +/- to suit.
    paul, Feb 8, 2005
  4. Sheldon

    Ed Ruf Guest

    Without the CPU, I believe the camera can't tell what the aperture is so it
    can not meter at all.
    Ed Ruf, Feb 8, 2005
  5. Sheldon

    DoN. Nichols Guest

    Correct. Some other cameras, such as the N90s film camera, have
    a second moving tab to tell the camera what the current aperture setting
    is (correction to this below), and those will work in aperture-preferred
    mode, although not in shutter-preferred mode.

    O.K. While I knew that was a proper description of the way such
    lenses would be used on the N90s, It did not seem to make any sense,
    without the camera knowing what the maximum aperture of the lens was.

    So -- I just dug out the N90s and several lenses, and discovered
    that what the ring and tab *actually* tell the camera is how many stops
    below the maximum aperture the lens is currently set to. So -- it can
    correct the measured light at full aperture to what will actually get
    through at the moment of exposure.

    And this is why the D70 will *not* work in any auto mode with
    these older lenses (at least until someone transplants a CPU into the
    lens). While it has a sensor to tell when the lens is set to the
    minimum aperture (so the range of apertures is available through
    controlling the motion of the stop-down lever inside the lens mount
    ring), it has no way of knowing what the maximum aperture of the lens
    is, or how many stops below that may be currently selected.

    I hope that this helps,
    DoN. Nichols, Feb 8, 2005
  6. Sheldon

    paul Guest

    So the camera doesn't know what aperture is being used but even in
    manual mode, the meter picks up a signal & tries to tell you +/-. It
    seems you could set aperture on the camera dial to match the lens & even
    run in aperture priority mode but I don't know. The point is there is a
    light meter in there no matter what reading what hits the sensor just
    like the green dot for focus apparently works with non-af lenses.
    paul, Feb 9, 2005
  7. Sheldon

    George Guest

    Is Pacific Rim Camera out of the conversion kit for your lens? They bought
    the remaining Nikon conversion kits and it is much nicer than having a notch
    into your lens.
    George, Feb 10, 2005
  8. Sheldon

    DoN. Nichols Guest

    [ ... ]

    [ ... ]
    I don't know. I had not heard of them until this moment. Do
    you have contact information for them?

    Never mind -- a quick web search found them, and I do find it
    quite interesting what is there. What I find for the lens in question


    Which based on the wording, and also on the photos on some other
    nearby ones, is purely the replacement aperture ring to provide the tabs
    to communicate with the N90s and similar. My lens (in the 168xxx serial
    number range) already has *that* conversion.

    What I was talking about was the installation of a CPU to tell
    the D70 what the maximum aperture is, so it can do its metering magic.
    The "AI conversion" would also be necessary if I did not have that.

    However, I can see that I should check through for certain other
    lenses which I may wish to so modify.

    Nope -- my favorite lens is not among those listed, so I guess
    that it is time to do some precision machining -- to convert that for
    use on the N90s, if not the D70. At least, I now know what to do,
    thanks to this discussion prompting me to study just how the mechanical
    coupling mechanism works, and I have the machine tools needed to do that

    Now, if I only had the means to add a CPU to the 80-200mm zoom,
    I would be really happy.

    DoN. Nichols, Feb 11, 2005
  9. Sheldon

    George Guest

    Sorry, my mistake...I thought you were looking at the AI conversion (didn't
    know anyone
    hadn't done that) and not chipping the lens. If you do have the lens
    chipped, please report
    back on your experience...I was considering having it done to a fisheye
    (8mm) but have been
    leery after seeing one posting on the newsgroups that reportedly had a bad


    George, Feb 12, 2005
  10. Sheldon

    DoN. Nichols Guest

    The fellow who does the chipping has removed the 80-200mm from
    the list of ones which he will work on. Presumably he found that was
    more difficult than he had otherwise expected.

    He *has* done my 180mm f2.8, and I am quite pleased with the
    results. (Other than the fact that it lies to the camera, claiming that
    it is a 300mm instead of a 180mm, bu that doesn't hurt anything, as I
    don't *have* a 300mm to confuse it with. (And it actually has coverage
    close to a 300mm on a full-frame 35mm camera. :)

    And I have a 20mm which I plan to send to him for chipping --
    some of these days. (He also does not chip the 16mm fisheye, which is
    my only other with the AI ring other than the 28-105mm which is my
    everyday lens.)

    I am considering setting up the necessary fixturing to modify the
    aperture ring on an older 50mm f1.4. That one is not covered by the NOS
    spares which I just looked at, so if it is to be converted to AI, I will
    have to do it myself from scratch. (I at least have the skills and
    the machine tools to do this at need.)

    Then comes the question of whether that one can be chipped.

    DoN. Nichols, Feb 12, 2005
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