Oops, I did it again!

Discussion in 'Digital SLR' started by Bruce, Oct 17, 2010.

  1. Bruce

    Bruce Guest

    Oops, I did what again?

    I foolishly spent some of my hard-earned pounds sterling on a lens ...
    .... a lens made by Sigma!

    It's a 12-24mm f/4.6-5.6 EX DG HSM in Nikon AF-D mount. I borrowed
    one a couple of weeks ago and the focusing motor broke. But I was
    reasonably pleased with the results. So I tried another one, and
    bought it.

    Strengths: It is optically quite competent with very good sharpness
    across the frame at 1/8 to f/11. It has remarkably good flare
    resistance for a lens of its type. The rectilinear distortion is
    remarkably well controlled.

    Weaknesses: It is soft at the edges wide open. It has strong
    vignetting wide open at 12mm which reduces to next to nothing at f/8.
    The zoom ring has varying resistance to being turned depending which
    focal length you start from and which way you go. The fixed lens
    hood is crudely shaped and would benefit from more careful design. The
    front lens cap is an abomination consisting of a push-on cylindrical
    adaptor with a thread for an 82mm dia. lens cap (a one piece cap would
    be better as no-one in their right mind would use filters on a lens
    like this). It is a Sigma so the build quality is dubious.

    Overall: A pleasant surprise, until it breaks. ;-)

    So why did I buy it? It is a cheap, temporary replacement for my
    AF-S Nikkor 14-24mm f/2.8G. I also bought a Tokina 28-80mm f/2.8 and
    a well-used Nikon D3 body for the same reason.

    When the situation regarding the successor to the Nikon D700 is
    clarified early in 2011, I will make some longer term decisions
    regarding what equipment to lease. Until then, I'm shooting rather
    more cheaply. ;-)
     
    Bruce, Oct 17, 2010
    #1
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  2. Bruce

    peter Guest

    And you ask us to believe what you say. Sheesh!
    what BS.
     
    peter, Oct 17, 2010
    #2
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  3. I can't speak to whether Mr. Polson actually owns the lens (or
    any other gear), but I've owned a Sigma 12-24mm for quite a
    while now. He's not that far off.

    I disagree with his assessment of flare resistance and of
    the hood in general. The only varying resistance I've found
    in the zoom ring is that it takes slightly more effort when
    zooming out from about 16mm to 12mm.

    To me, the back lens cap is more of a design flaw than the
    front one. I _have_ used a GND filter on this lens, but
    only at about 20-24mm and with a DX format dSLR.

    I have no complains about build quality, but sample variance
    is another matter. A friend of mine and I swapped copies for
    a couple of shots as an experiment -- he ended returning his.
     
    Michael Benveniste, Oct 17, 2010
    #3
  4. 12-24mm with 82mm Polarizer:
    http://wemightneedthat.biz/Images/12-24.jpg
     
    Michael Benveniste, Oct 18, 2010
    #4
  5. Bruce

    Bruce Guest


    What possible use is a polariser on a lens of this focal length range?
    Even at 24mm on APS-C, there are very few shots where a polariser
    would give a useful result.
     
    Bruce, Oct 18, 2010
    #5
  6. Bruce

    Bruce Guest


    I tested the built-in hood with a point light source at 12mm on the
    edge of the lens's angle of view on full frame (Nikon D3). I found
    that the effectiveness of the shading varied considerably because of
    the crude shape of the "petals". A more careful design would have
    given more shape to the petals so as to give more even shading.

    I note that you use APS-C so your experience will be entirely
    different, and therefore almost irrelevant because the crude built-in
    hood offers no shading at all for APS-C users. There should really be
    a separate hood for APS-C use.

    The even cruder 'lens cap adapter', if used as a hood - a purpose for
    which it surely cannot have been intended - causes vignetting at focal
    lengths shorter than 21mm on full frame, so presumably about 14mm on
    APS-C.
     
    Bruce, Oct 18, 2010
    #6
  7. Bruce

    Bruce Guest


    How many years have you had yours, and what sort of use has it had?

    I ask because, given past experience with Sigma glass, I don't have a
    lot of faith in its longevity. ;-)

    It's surprisingly good optically, though, while it lasts.
     
    Bruce, Oct 18, 2010
    #7
  8. I eagerly await your posting of your test.
    Ever hear of this stuff called 35mm film? I bought the 12-24mm
    well before I bought a dSLR.
     
    Michael Benveniste, Oct 18, 2010
    #8
  9. Bruce

    Bruce Guest


    Funny, I had the same reaction from the sales person. But the Sigma
    UK three year warranty helped.


    There is a thin metal C-shaped clip, rather like a circlip, that
    surrounds the rear element. You can slide a gel filter under it. The
    clip is matt black and it is easy not to notice it against the matt
    black surround to the rear element.

    However, this is a risky business as the gel is likely to end up with
    a crease in it and there is a high probability of contact with the
    rear element. You have to cut the gel to suit.

    It all looks like a bit of an afterthought. I doubt I will use it.

    Thanks, Paul.
     
    Bruce, Oct 18, 2010
    #9
  10. I once compared *on film* (and FF) the Sigma 12-24mm at 12mm, the
    Nikkor 15mm f5.6, and the Voightlander 12mm f5.6. With *these particular
    samples* at the test aperture (either at f8, or more likely, at f11), the Sigma
    had somewhat soft corners and almost acceptable edges; the Nikkor had
    OK corners and good edges; the Voightlander had good corners and very
    good edges (at least, best I can remember...;-). I have since checked
    various lenses that I still have that performed well on film again on digital,
    and would down-rate the 15mm considerably, as well as the 20mm (the
    24mm, 28mm, 35mm, 50mm, and 85mm AF lenses performed well on
    APS-C digital at f5.6 to the corners at infinity, my usual lens comparison
    distance). BTW, my MF Sigma 8mm f4 also performed well at f5.6 on
    digital to the edges, and the Nikkor 16mm f3.5MF was, as usual, excellent
    everywhere. WHAT a lens that is! ;-)
    --DR
     
    David Ruether, Oct 18, 2010
    #10
  11. Bruce

    Bruce Guest


    You would use a polariser on such an ultra-wide angle lens? Why?

    More to the point, don't you know why you shouldn't?
     
    Bruce, Oct 18, 2010
    #11
  12. Bruce

    Bruce Guest


    Precisely.
     
    Bruce, Oct 18, 2010
    #12
  13. Bruce

    peter Guest

    How many landscape shot have you exhibited, never mind sold.
     
    peter, Oct 19, 2010
    #13
  14. Bruce

    peter Guest

    Shh! Brucie is not interested in anything he can't bluster about.
    Of course you're right.
     
    peter, Oct 19, 2010
    #14
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