Advise on Nikkor lens

Discussion in 'Digital SLR' started by dirk van lut, Oct 7, 2008.

  1. dirk van lut

    dirk van lut Guest

    Hi all,

    I've got following lenses already for my D300.

    a 15-55/2.8 in DX format
    a 70-200/2.8 (converted to DX = 105-300)

    As you can see, there is a gap in the area 55 to 105.

    Would the Nikkor 28-70/2.8 (converted to DX = 42-105) be a good choice?

    Any other suggestion are welcome.


    Dirk van Lut
    dirk van lut, Oct 7, 2008
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  2. dirk van lut

    Me Guest

    I presume you man a 17-55mm (not 15-55). It's a DX format lens, but
    still 17-55mm - not "17-55mm 35mm equivalant".
    Your gap is between 55 and 70mm.
    So between about 80 and 105mm in 35mm equivalent.
    With the 28-80 instead of the 17-55, I'd sure miss the big 17-28mm gap
    much much /much/ more than the small gap between 55 and 70mm.
    In fact, I'd miss the 55-70 (equivalent) gap not at all, as almost
    always a small step back or forward would re-frame the subject.
    Me, Oct 7, 2008
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  3. dirk van lut

    Me Guest

    Oops - delete the last (equivalent) typo.
    Me, Oct 7, 2008
  4. dirk van lut

    dirk van lut Guest

    Hi Me, thanks

    Let's talk in DX formats as I have only a D300 and forget for the time being
    the 35 mm equivalent (D700 and D3 still to expensive for the time being!)
    The range I have now is 17-55mm and 105-300 (in DX terms).
    So the gap is 55-105 in DX terms.
    Or do I have it wrong? Please explain?

    dirk van lut
    dirk van lut, Oct 7, 2008
  5. dirk van lut

    Me Guest

    You have it wrong.
    The 17-55 DX lens is around 27-80mm in 35mm terms
    The 70-200 is around 105-300mm in 35mm terms.

    The focal length is the focal length - regardless of format (Dx or Fx)
    that the lens was designed for.
    Me, Oct 7, 2008
  6. dirk van lut

    N Guest

    If you're trying to avoid the "crop factor" expression, why not just talk
    about angle of view, which defines what the resulting image will contain.
    N, Oct 7, 2008
  7. dirk van lut

    J. Clarke Guest

    Forget about "DX terms". What are the numbers that are actually
    marked on the lenses?
    J. Clarke, Oct 7, 2008
  8. No, there isn't. The focal length of a lens is a physical property of
    that lens and has nothing to do with which body (DX or FF) it is used

    Forget those "converted to DX format". That is nonsense. If at all you
    might say
    "The magnification/field of view of a 70mm lens (no qualifier!) on a DX
    body is similar to the magnification/field of view of a 105mm lens on a
    FF body."

    The DX designation on the 15-55 simply means that the lens illuminates a
    smaller image circle than a full-frame lens and therefore when used on a
    FF body the corners will probably suffer from shading aka vignetting.
    Otherwise it's an honest to god 15-55mm lens and there is no "converted
    to DX".

    Your gap is between 55 and 70mm and that is so small that most likely
    you won't notice it. It is more a question of convenience. If you are
    shooting a lot in the light tele length area, e.g. portraits then
    currently you may have to swap lenses a lot because you may be switching
    between just shorter and just longer then the gap. An additional lens
    like the one you propose below would eliminate that swapping.

    Jürgen Exner, Oct 7, 2008
  9. No, don't! The focal length of a lens has NOTHING to do with the body.
    And _ANY_ SLR lens is marked with the actual physical focal length of
    that lens.
    What are those numbers that are engraved on on your lenses?
    No, you don't.
    No, don't do that. It will only confuse you.
    Yes, very much so.
    Those lenses have focal lengths of 17-55 and 70-200. Period!

    Their respective field of view/magnification factor on a DX body
    corresponds to what you would get from a 26-82 and a 105-300mm lens on a
    FF body. But that's it. The lens doesn't change and it's focal length
    doesn't change.

    Jürgen Exner, Oct 7, 2008
  10. dirk van lut

    dirk van lut Guest

    Many thanks all of you and especially Jurgen for his clear explenation.

    You've clarified the mis-thinking I had between focal length and the crop


    Dirk van Lut
    dirk van lut, Oct 7, 2008
  11. dirk van lut

    dirk van lut Guest

    So what is the advantage of DX lenses?? (if any)
    dirk van lut, Oct 7, 2008
  12. dirk van lut

    Alan Hoyle Guest

    DX lenses can, in theory, be smaller, lighter, and less expensive than
    lenses with the same focal lengths and apertures that can cover FX

    Alan Hoyle, Oct 7, 2008
  13. Because they need to illuminate a smaller area only (the DX sensor
    instead of the larger FF sensor), they are easier to design and build,
    smaller, lighter, and also cheaper than their FF siblings.

    Some people also claim they optimize the light ray direction for
    electronic sensors (hitting the sensor more vertically) and additional
    coating prevents back reflection. I do not know if this is true. If it
    is then it should apply to modern FF lenses, too, because digital
    cameras are the standard nowadays.

    Jürgen Exner, Oct 7, 2008
  14. Dirk,

    I ended up replacing the 18-55mm "kit" lens with the 16-85mm VR lens, but
    it's a smaller aperture than you may need. I also have the compact
    70-300mm VR lens.

    Hence 70-85mm overlaps with these lenses.

    David J Taylor, Oct 8, 2008
  15. Why do you believe you need to fill the gap at all? I suggest that you
    use the lenses you have for a few months and see. Why spend money to get
    a lens that you might not even need?

    FWIW: I've been shooting professionally for 30 years. My old 35mm film
    system consisted of just 6 lenses: 24mm, 35mm, 50mm, 85mm, 180mm +
    matched 2x extender; no zooms. I shot 99% of all my 35mm assignments
    with just those lenses, and never even needed those in-between focal
    lengths. In fact, I could have almost gotten along without the 50. Only
    had need of it once a year or less, but when I needed it, I needed it.

    So, don't think you need to cover ever millimeter between you widest lens
    and you longest to take good pictures. You don't.

    Stefan Patric, Oct 8, 2008
  16. dirk van lut

    Paul Furman Guest

    85mm f/1.4 :)
    This is true, it's minor.

    Paul Furman

    all google groups messages filtered due to spam
    Paul Furman, Oct 9, 2008
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