Help with lens evaluation, please.

Discussion in 'Lens Lust' started by Uncle Frank, Mar 31, 2005.

  1. Now that the rush of elation about getting my new lens is over, I've been looking critically at the
    initial results, and decided to to do a little measurebating. I'd like to solicit some opinions on the results.

    Comparisons are between the Nikon 60/2.8 micro, the Nikon 28-70/2.8, and Nikon 80-200/2.8. Shots were
    taken on tripod, using the self timer to trigger the shutter. These are unresized crops". Processing was
    limited to auto-levels.

    The first image is each set is of the 60mm prime, followed by the 28-70mm/2.8 at 70mm, and the
    80-200mm/2.8 at 80mm.

    At full aperture

    41478473.
    41478474.
    41478475.

    At f/4

    41478476.
    41478477.
    41478478.

    At f/5.6

    41478479.
    41478480.
    41478481.

    At f/8

    41478482.
    41478483.
    41478484.

    It seems that the 28-70/2.8 doesn't get competitive until f/5.6. Is this normal, or is there a problem?
     
  2. IMHO I think your lens looks very fine.

    The best test you can make is with a roll of slide film. Some lenses will behave differently on a D70 VS D100 VS D2H VS D2X... Besides, this is a 100% crop. F2.8 is very acceptable and of course, you are supposed to get better results from the micro lens, especially at a closer distance.

    I know my 28 1.4 was totally crappy in my D100 and it shines on the D2H.
     
  3. Thanks for the input, NB. I'd try the lens with slide film, but I can't figure out how to cram in into my d70 :?.

    In truth, I expected the 28-70 to give results equivalent to the 80-200 at f/2.8, so I became concerned
    when I saw the comparitive results. Maybe I just need to reset my expectations, but the 28-70
    doesn't seem significantly better that my recollection of images from the 24-120VR, and not as sharp
    as the Tamron 28-75 at f/2.8.
     
  4. tweber

    tweber

    372
    Feb 12, 2005
    St. Louis
    My thoughts

    Frank,

    The 2.8 certainly looks soft by comparison. I no longer own the 28-70 so can't offer much. I recall though that it was darn good wide open. Have you tried any real world shots wide open?

    Tom
     
  5. Re: My thoughts

    Yes, but most of them were taken at very low shutter speeds, hand held, so I can't draw any conclusions
    from them. I need to do a little more real world testing instead of shooting newspapers.
     
  6. What I see is that the 80-200 isn't much sharper at wide aperture... I also see the 28-70 lacks a bit of contrast at wide aperture, which isn't a bad thing either.

    The usual USM will fix it easily.

    The way I see things: for normal photographs that will get quickly printed, no PP is acceptable and the sharpness is fine.
    Once you want to blow-up the keepers, then you'll play with black, gray and white point, play with curves and contrast and then add USM. All this will bring the quality where it's supposed to be.

    Your 28-70 example reminds me of my 80-200mm 1 ring version wide open.

    I understand you tested only at 70mm but what really is important on the 28-70 lens is the wide end. This is what makes this zoom special. If it's soft at 28, then you should return it. I believe the key to look after is on the wide end.
     
  7. nfoto

    nfoto Guest

    Hand-held shots for testing sharpness? You must be joking, right?
     
  8. Is it normal?

    nt
     
  9. dkapp

    dkapp

    122
    Mar 18, 2005
    San Francisco
    I use the 17-55 & these 28-70 shots look soft to me. Here is a quick shot I just took of the Feb 2005 Issue of National Geographic cover. This was was shot handheld, at fairly slow speed (exif below). I'm sure I could do better with a tripod & shutter release, but its in my gf's car.

    I just did levels & cropped for 100% to keep the test somewhat standard.

    [​IMG]

    I can get the tripod out around 4:00 today for a better test if you'd like, but this should give you an idea.

    ------------------------------------------------------------
    File name: _D2H2605_2.jpg

    Camera make: NIKON CORPORATION
    Camera model: NIKON D2H
    Date/Time: 2005:03:31 12:07:20
    Flash used: No
    Focal length: 55.0mm
    Exposure time: 0.033 s (1/30)
    Aperture: f/2.8
    ISO equiv.: 200
    Metering Mode: matrix
    Exposure: aperture priority (semi-auto)

    Hope this helps.

    Dave
     
  10. nfoto

    nfoto Guest

    My comments are refering to the fact that corners of the image (used on F5) are less sharp unless you stop down a couple of stops, to say f/5.6. this is due to field curvature and would be less important on a DSLR/DX-format.

    Also note that most zoom lenses will have more field curvature when they are focused close. this propensity differs between lenses so it is unwise to compare lenses focused on near subjects.
     
  11. dkapp

    dkapp

    122
    Mar 18, 2005
    San Francisco
    I just found my old tripod. Another shot to come in a few minutes.

    Dave
     
  12. dkapp

    dkapp

    122
    Mar 18, 2005
    San Francisco
    Another from inside the National Geographic. This time I used a tripod & remote. Just auto levels & 100% crop. Image data below.

    Is this helping, or are we comparing apples to oranges?


    [​IMG]

    ------------------------------------------------------------
    File name: _D2H2607_2.jpg

    Camera make: NIKON CORPORATION
    Camera model: NIKON D2H
    Date/Time: 2005:03:31 12:26:43
    Flash used: No
    Focal length: 55.0mm
    Exposure time: 0.033 s (1/30)
    Aperture: f/2.8
    ISO equiv.: 200
    Metering Mode: matrix
    Exposure: aperture priority (semi-auto)

    Dave
     
  13. STOP THE PRESSES!

    I've been reviewing my methodology, and it sucked :oops:.

    I took my unresized samples from the top of the page, not the middle. I re-did the test, using a center crop, and the results are entirely different (duh).

    original.


    original.


    original.


    original.

    Conclusions:

    I'm a weenie.
    I"m gong to leave the lens testing to the pros.
    The 28-70 looks just fine.

    Thanks to all for helping me get over my panic attack.
     
  14. MontyDog

    MontyDog

    Jan 30, 2005
    #1064 - You have an error in your SQL syntax;
     
  15. MontyDog

    MontyDog

    Jan 30, 2005
    #1064 - You have an error in your SQL syntax;
     
  16. MontyDog

    MontyDog

    Jan 30, 2005
    #1064 - You have an error in your SQL syntax;
     
  17. It was just a mild panic attack, NB. Thanks for helping me work my way through it.

    I think I'll use Chris's approach from here on out. I won't let testing get in the way of my subjective
    pride of ownership :twisted:.
     
  18. i'm with you Frank. If i bought it it is good at least for a while.
     
  19. Flew

    Flew

    994
    Jan 25, 2005
    Alabama
    Hey Frank,


    Unless you are Bill Gates or some other rich SOB, it is hard not to have buyers remorse, especially when you are spending hard cash on a hobby. Your panic is completely understandable. ;-)

    Glad everything turned out OK. BTW, I agree with your assessment on one thing; leave the lens testing to Ron and Bjorn.... :lol:

    Frank
     
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