Sigma "DC" 18mm F3.5 - 200mm 6.3 on my Pentax *ist D

Discussion in 'Pentax' started by Gaderian, Aug 28, 2005.

  1. Gaderian

    Gaderian Guest

    Perhaps more of a technical question but here it goes.
    Bought a new lens (see subject line) made specifically for my type of DSLR.
    I love the range because I'm going on a trip and the wide range will
    minimize the swapping of lens and I can use a smaller camera bag. I've been
    told that the trade off is that my other lenses (Pentax SMC 18-35, 28-80,
    300) will result in sharper more colourful results than the wide range. Is
    this true?

    So far I've been happy with the new lens but I haven't really had a chance
    to use it under all conditions.
    Any input appreciated.
    Gaderian, Aug 28, 2005
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  2. Gaderian

    Paul Mitchum Guest

    If you were unsure about the lens, why did you buy it?
    Paul Mitchum, Aug 28, 2005
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  3. Gaderian

    Toa Guest

    Gee, that's helpful advice

    Toa, Aug 28, 2005
  4. Gaderian

    Toa Guest

    told that the trade off is that my other lenses (Pentax SMC 18-35, 28-80,
    My "guess" is that there's usually a trade off in these situations. How
    much applies in this case could be arguable as some folks are quite picky
    about minute detail while others aren't. You may be quite happy with the

    My suggestion is to just get out and take some good comparative shots and
    compare the results.

    Personally, while travelling I'm prepared to sacrifice some slight loss in
    image quality if it means getting "the shot" instead of wasting time
    repeatedly swapping out lenses.

    Toa, Aug 28, 2005
  5. Gaderian

    birdman Guest

    I own this lens.
    This is not the world's greatest lens but is actually a very good performer
    for what it is and far superior to the horrible 28-200/300 genre for 35mm
    cameras, probably because the lens only has to cover the size of the smaller
    dSLR sensor.
    I bought the Sigma for travel after trying and returning 3 new Nikon
    55-200mm lenses.
    To be charitable, the Nikon 55-200 is an utter piece of garbage that cannot
    focus and has terrible optical and mechanical problems completely washed
    over in the review in PopPhoto (in 30 years of reading that magazine I have
    never seen a review of a piece of equipment that was such an absurdity). In
    over 30 years of using Nikons, obviously I like Nikon, I have never seen
    anything made by Nikon for SLRs that was of such poor quality as this new
    55-200mm lens.
    No one should buy that lens, but they will. It is no bargain at a retail
    price of $280.
    The Sigma totally outperforms the Nikon in the 55-200 range. It is sharp,
    contrasty, has low flare and low distortion. The Sigma can actually find
    focus rapidly while the 55-200 hunts and pecks due to imprecision with its
    autofocus mechanism and what must be execrable flare and low contrast such
    that the camera autofocus sensor cannot find adequate maximum contrast.
    Look at a point source of light with your favorite lens, the Sigma 18-200
    and the Nikon 55-200. The issues become obvious.
    The Sigma has slight vignetting at lowest focal length shooting wide open
    that disappears within about two f stops.
    At the widest angle/lowest focal length distortion may be visible, depending
    on subject matter. It disappears by dialing in a setting of 2-4 in the new
    Photoshop CS2 lens/distortion filter! The Nikon kit lens that comes with the
    D70 is a bit better at the lowest focal length because of less distortion.
    Put it this way: I just got back from a three week trip in Asia with the
    Sigma 18-200 on a D70 (raw only). I have no complaints about the lens, which
    for me is very unusual. I can't blame the lens for my aesthetic shortcomings
    .. . .
    birdman, Aug 28, 2005
  6. I use this lens on a Canon 300D. It has performed better than I
    expected for a lens of its range and price. Typically, a lens of lesser
    range should perform better the one of a wider range but that isn't
    always the case. IMO, I think the Sigma 18-200 generally performs much
    better than any two other zoom lenses that might cover its range that
    are priced around $200 each. Of course, if you spend more for quality
    lenses then they will perform better.

    I find it odd that Canon does not offer a lens in this range as it is
    very convenient to have one lens cover such a variety of situations.
    The Sigma is not the best choice for low light but with sufficient
    lighting it can produce very good results when used at f/8 or smaller.
    I haven't found anything about the lens that really bothers me. It has
    good sharpness, clarity and contrast. I've noticed little vignetting
    and CA/fringing. Also, focus speed seems to be very good for my use.

    If I could only take one lens for a given situation it would definitely
    be this one. What I give up in quality is more than made up for by the
    convenience. Besides, I have taken some good candid shots that I would
    never have gotten if I had to stop and change to a different lens. The
    moment would have passed. I will take a good photo with a little less
    quality over not getting a photo at all.
    Michael Johnson, PE, Aug 28, 2005
  7. Gaderian

    Gaderian Guest

    Who says I was unsure? You just made an assumption.
    This question is a result of a person who prompted me to ask this question
    "after" I bought the lens.
    Too bad you are incapable of articulating the original post and contributing
    to this news group.
    Gaderian, Aug 28, 2005
  8. Gaderian

    Gaderian Guest

    Precisely why I bought the lens.
    Also I'll be traveling to a few countries where the environment can be dusty
    and I wanted to lighten the load.
    Thanks or your input!
    Gaderian, Aug 28, 2005
  9. Gaderian

    Gaderian Guest


    Excelent input! Thanks!
    Gaderian, Aug 28, 2005
  10. Gaderian

    Gaderian Guest


    Thanks for your input Michael (you too Toa and Birdman).
    Gaderian, Aug 28, 2005
  11. Generally speaking, yes. It's harder to design, build, and assemble a
    very wide-range zoom lens than a fixed-focal-length or smaller zoom
    range lens. A wide-range, cheap lens is always slow (small maximum
    aperture), and generally somewhat soft at one end or the other
    compared to the best lenses of the focal length.

    On the other hand, often the difference isn't big enough to show to
    most people in a 4x6 print.
    Checking it out in your own uses and comparing it to your other lenses
    is the best way to reach your conclusion. If you do that, your
    conclusion will be right for you, regardless of what the rest of us
    David Dyer-Bennet, Aug 29, 2005
  12. Gaderian

    Paul Mitchum Guest

    If you've been happy with the lens, what's the problem? If you have the
    other lenses, you can compare. Reading a newsgroup won't give you a
    basis for comparison; if you've got all four lenses, figure out some
    shooting tests and shoot. Figure out if there are any down sides to the
    superzoom. If there are, figure out if they're worth it to only carry
    one lens.
    Paul Mitchum, Aug 29, 2005
  13. While all of that is true, it simply misses the point. Yes he
    has the lenses, and can make the comparisons, but it still is
    nice to compare notes with others and learn from their
    experience. That is particularly true when it is possible that
    others may have a much wider range of experience and/or talent.

    Regardless of that, it is an interesting topic and one of
    significance right now because there are new wide range zoom
    lenses on the market. I would be very interested in hearing
    about comparisons for 28-300mm zoom lenses. I just purchased a
    used Nikon D1 with a 80-200mm f2.8 Nikon AF and a 20mm f2.8
    fixed lens. I need both a "normal" lens and a longer lens too;
    hence I've just started looking at these 28-300mm f3.5/6.3 zoom
    lenses and obviously would greatly benefit from other's
    experiences *before* making any decisions on what to purchase.

    It appears, at initial first blush, as if one of the 28-300mm
    f/3.5 zoom lenses (Tameron seems good, as does Sigma) would be
    ideal. The new versions are relatively smaller and lighter than
    the older versions. The Sigma lens costs a little more, but not
    much. The Sigma lens has slightly greater maximum magnification
    (1:3.8 vs 1:2.9) and weighs slightly less (.84lb vs .93lb).
    They both use the same filter sizes, have the same f-stop range,
    and minimum focus distance.

    Given that these lenses are intended for 35mm they should
    provide excellent sharpness on a digital camera with a smaller
    "film size"??? And packing a one pound lens around should be
    far more convenient that packing 2 or 3 lenses (particularly when
    one is a large 80-200mm zoom, even if it is a superb lens).

    So, the question is... how do these lenses stack up against
    each other, and against the definitely higher quality Nikon
    Floyd Davidson, Aug 30, 2005
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