Tamron 28-75/2.8 vs Minolta 28-75/2.8

Discussion in 'Minolta' started by Bill Tuthill, Feb 16, 2005.

  1. Bill Tuthill

    Bill Tuthill Guest

    Pop Photo tested the Minolta 28-75/2.8 was tested for their Feb 2005 issue.
    The optically similar Tamron 28-75/2.8 Di was tested last year; I'm not
    sure when, but I wrote down SQF scores, unfortunately just grades and
    not numbers. Even so, there is a big discrepancy at the long end. Viz.
    It appears that in exchange for lower distortion, the K-M is less sharp.

    Tamron Minolta
    16x20 20x24 16x20 20x24
    28mm 28mm
    2.8 A B A B
    4 A B+ A B+
    5.6 A B+ A B+
    8 A B+ A B+
    11 A B+ A B+
    16 B+ B B+ B
    22 B+ C+ B+ C+
    50mm 50mm
    2.8 A B+ A B+
    4 A A A A
    5.6 A+ A A+ A
    8 A+ A A+ A
    11 A A A A
    16 A B+ A B+
    22 B+ B B+ B
    75mm 75mm
    2.8 A B+ B+ B
    4 A B+ A B+
    5.6 A+ A A B+
    8 A+ A A B+
    11 A A A B+
    16 A B+ A B
    22 A B+ B+ C+

    28mm .6% barrel .79% barrel
    50mm .86% pincushion ? .51% pincushion
    75mm 1.28% pincushion ? .51% pincushion

    (One or the other .51% might be in error)
     
    Bill Tuthill, Feb 16, 2005
    #1
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  2. Bill Tuthill

    Alan Browne Guest

    Bill, please refresh us on how the scores are derived. Is it subjective or
    measured?

    It is odd that the lenses are identical up the middle and then the long end is
    so different.

    Cheers,
    Alan
     
    Alan Browne, Feb 16, 2005
    #2
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  3. Bill Tuthill

    Bill Tuthill Guest

    Pop Photo claims they bought an MTF measuring machine, so the numbers
    are based on edge sharpness extrapolated to how negatives would appear
    at various degrees of enlargement.

    Tony Polson thinks they make up the numbers over a 3-Martini lunch.

    Unlike Photozone.de and Photodo.com, which correlate strongly with
    the results I see from the lenses I know, with some minor exceptions,
    SQF numbers do not have an ultra-strong resemblance to results. Also
    Pop Photo sometimes changes SQF numbers several months after testing
    when vendors or readers(?) complain.

    The K-M 28-75/2.8 isn't much better than the Sigma 18-125/3.5-5.6 DC
    according to SQF. I posted Sigma 18-125 numbers over in r.p.digital.
     
    Bill Tuthill, Feb 17, 2005
    #3
  4. Bill Tuthill

    Alan Browne Guest

    Thanks Bill. I was wondering if they actualy made all those large prints and
    then sat around and rated the results. It would be nicer if they'd just put up
    graphs.

    Photodo have been dead for a couple years now.

    I haven't been checking Chasseur D'Images issues at the store, they always have
    5 or 6 lens tests and they are very well done. Last year (as I posted) they
    changed to an all digital system that rates lens-body combos (which makes things
    complicated for the future as new bodies come out).

    Cheers,
    Alan
     
    Alan Browne, Feb 17, 2005
    #4
  5. Bill Tuthill

    sebastiaos Guest

    That`s silly :)
    This is exactly the same lens!!
    Tamron is producing this lens for minolta.

    sebastiaos
     
    sebastiaos, Feb 21, 2005
    #5
  6. Bill Tuthill

    Alan Browne Guest

    If that's true then either Tamron has sloppy manufacturing or Pop Photo have
    sloppy measuring. I'd bet the later.

    Other conspiracy theories may emerge.
     
    Alan Browne, Feb 21, 2005
    #6
  7. AnOvercomer 02, Feb 21, 2005
    #7
  8. Bill Tuthill

    Alan Browne Guest

    Like the Freemasons, a very badly kept secret.
     
    Alan Browne, Feb 21, 2005
    #8
  9. AnOvercomer 02, Feb 22, 2005
    #9
  10. Bill Tuthill

    Alan Browne Guest

    a) this is OT.

    b) er, never mind.
     
    Alan Browne, Feb 22, 2005
    #10
  11. Yeah, you don't want to go there.
     
    Brian C. Baird, Feb 22, 2005
    #11
  12. Bill Tuthill

    Peter Chant Guest

    The question is, if you formed a world government would you opt for the
    Tamron or the Konica-Minolta?
     
    Peter Chant, Mar 9, 2005
    #12
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