First shots using D50 + Tamron 17-50 f2.8. C&C welcome.

Discussion in 'Digital Photography' started by cutsman, Oct 21, 2007.

  1. macrumors regular

    Joined:
    Jun 1, 2006
    #1
    Purchased a Tamron 17-50 f2.8 to replace my kit lens about 2 weeks ago. Finally got the chance to try it out this weekend. These were taken Sunday afternoon. I'm really liking this lens so far. Let me know what you guys think. As always, C&C is always appreciated! Thanks!

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  2. macrumors member

    Joined:
    Dec 10, 2005
    Location:
    New Zealand
    #2
    Wonderful. Appreciate the post, I too am seriously going to swap out my kit lens for this very same Tamron - so thanks again for posting - great pic's
     
  3. macrumors 6502

    Joined:
    Mar 10, 2007
    Location:
    MI
    #3
    Love the last two, the first is interesting in that the leaf in the foreground is mirrored in the back, don't know what term that is. But that tamron is a great lens, sure do miss it.
     
  4. macrumors 6502

    Joined:
    Jun 26, 2006
    Location:
    Southern California
    #4
    Never regretted getting this lens.
     
  5. macrumors 6502

    Padaung

    Joined:
    Jan 22, 2007
    Location:
    UK
    #5
    Photos looking good. Liking the first one a lot.
    Were any of the photos shot at 2.8?

    I've had 2 copies of this lens - the first was sharp as anything at 2.8, but it got smashed when I knocked my tripod over and the lens took the force of the fall!

    My current copy of the same lens I need to stop down to around 4.5 before the shots are sharp - I didn't test the lens out when I first got the replacement either, as the first one I had was so good. It was only when I needed all the way to 2.8 a while later that I found this out.

    I've got a dud - grrrr.

    Had it too long to take back now, too. Kicking myself for not testing it, as should have known better.
     
  6. macrumors G4

    Joined:
    Jan 5, 2006
    Location:
    Redondo Beach, California
    #6
    This is the main difference between Nikon and third party lenses. Setting up a factory to do exact reproducible work is not cheap and easy. Quality control and testing is expensive.
     
  7. thread starter macrumors regular

    Joined:
    Jun 1, 2006
    #7
    These were the aperture settings for the photos:
    1. f4
    2. f2.8
    3. f4
    4. f8
    5. f2.8

    My informal testing has shown that f2.8 on my copy definitely does not seem as sharp as f4 and onwards. However, I'm not sure how much of this is actually attributed to the shallow DOF as opposed the lens actually not being sharp.
    Should I even expect f2.8 to be as sharp as the smaller apertures or is this unrealistic?
     
  8. macrumors G4

    Joined:
    Jan 5, 2006
    Location:
    Redondo Beach, California
    #8
    The best way to test is to shoot something flat, like
    a sheet of newspaper taped to a wall. The do 4X
    blowups of parts in the center and the edges. With my D50 I've found that the weak link as far as sharpness goes is the sensor. There is a low pass filter that blurs the image bonded to the CCD. I think this is why my lenses
    appear to have exactly equal sharpness. All of mine of Nikors

    Lenses are never perfect even if built exactly
    as designed. They will have some un-corrected optical
    aberrations. These will always be worse with wider
    apertures.

    On the other hand there is another law of optics that says a perfect lens will have resolving power proportional to the physical diameter (physical diameter, or focal length over f-stop) This is cause by the wave-like nature of light.

    The two rules balance together and the result is a curve. Typically it peaks at about one or two f-stops from wide open. But some very good lenses peak at maximum aperture. Canon publishes MTF curves for their lenses. I wish Nikon did
     
  9. macrumors 6502

    Padaung

    Joined:
    Jan 22, 2007
    Location:
    UK
    #9
    Too true. The Nikon equivalent is 3x the price though, and I don't go to 2.8 that often. Get what you pay for...


    It is normal for the extreme aperture results to be not quite as sharp as the mid range settings ie f5.6-f16 are normally the sharpest settings in all lenses. Again, there is sometimes a slight drop in sharpness as you get to the other extreme end of the lens' aperture range too (eg f22 with this Tamron lens). This is usually much less, if ever, an issue as it is so neglible.

    Third party lenses, as ChrisA so rightly said, have a reputation for more variance in the quality control of their lenses. Buy a pro Nikon/Canon lens and you know the chances are it will be top notch, even wide open. This Tamron lens is marketed as a pro lens, but as my example shows you can sometimes get a lens where the extreme wide aperture is unacceptable. It is unfortunately the same problem with Sigma and Tokina. This is the main benefit of buying such a lens from a store and not on-line - you can take it back and swap it easily.

    Your two shots at 2.8 are looking pretty good to me.
     
  10. macrumors 6502

    Joined:
    Jun 25, 2005
    #10
    There are very few, if any, lenses in the world that are as sharp wide open as they are at smaller aperture. Even $3500 Leica lenses improve as you stop down (though a wide-open Summilux will put many a lens to shame).

    At f/2.8 you're aiming for acceptable sharpness and from what I can tell here, these are definitely acceptable.
     

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