Site Sponsors
Results 1 to 5 of 5

Thread: DxO lens tets

  1. #1
    Sr. Administrator Jack's Avatar
    Join Date
    Oct 2007
    Location
    Los Altos, CA
    Posts
    10,786
    Post Thanks / Like
    Images
    1054

    DxO lens tets

    IMHO they are flawed...

    Compare their rating on 50mm lenses. Take their highest rated 50, the Outus 55 with a score of 50 and compare it to the freshman Nikon Z 50/1.8S with a total score of 44. Now compare each individual testing metric... The Nikon lens beats it by 6 points in sharpness, ties it in distortion, ties it in vignetting, loses to it by a measly 0.2 on transmission, and beats it by 4 on chromatic aberration. So why -- better HOW -- do they justify giving the Outus 4 more total points? In fact, the Sigma ART 50 BEATS the Outus on ALL test metrics except transmission (0.1) and CA (3 pts) -- so I guess those get somehow weighted 4 worse points than all the other wins totaled? What am I missing? Do they give extra points for max aperture? Oh wait, no because the Sigma is also f1.4... Do they give extra points for higher MSRPs? Do they take away points for AF???
    Jack
    home: www.getdpi.com

    "Perfection is not attainable. But if we chase perfection, we can catch excellence."
    Thanks 1 Member(s) thanked for this post

  2. #2
    Senior Member Darin Marcus's Avatar
    Join Date
    Jul 2018
    Location
    Northern VA, USA
    Posts
    510
    Post Thanks / Like

    Re: DxO lens tets

    The official explanation is presented here: https://www.dxomark.com/dxomark-lens...ting-protocol/

    In reality I suspect that other subjective criteria are also factored in...

    It's probably a good idea to ignore the overall score and look instead at the test results that matter to you

  3. #3
    Super Duper
    Senior Member
    pegelli's Avatar
    Join Date
    Dec 2010
    Location
    Belgium
    Posts
    3,754
    Post Thanks / Like

    Re: DxO lens tets

    You need to be careful when comparing the DXO lens sharpness numbers when tested on different MP sensors, I think the value they present for sharpness is how many of the sensor MP's are actually resolved in the test image. For the Otus that is 33 of 36.6 MP's (so ~90%) while for the Nikon 50/1.8 it's 37 out of 45.7 MP's (so 81%). I know these percentages are not directly comparable but you can only directly compare the sharpness measure when taken on the same sensor. So that might explain part of the difference in overall rating between these two lenses. You really need to test the Otus on a Z7 to make them comparable.

  4. #4
    Sr. Administrator Jack's Avatar
    Join Date
    Oct 2007
    Location
    Los Altos, CA
    Posts
    10,786
    Post Thanks / Like
    Images
    1054

    Re: DxO lens tets

    I hear you, but they for example claim their resolution is based on "perceptual mega-pixels" of resolution to eliminate the variable of sensor density. They also then say differences of 10% in their resolution scores can be ignored LOL. I understand it is somewhat of a moving target, that the Outus was tested 5 years ago when that kind of performance was awe-inspiring compared to the lenses on the market then, and now it has become more commonplace. Still, one would think they could have a bit more uniformity in their final total score comps...
    Jack
    home: www.getdpi.com

    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

  5. #5
    Super Duper
    Senior Member
    pegelli's Avatar
    Join Date
    Dec 2010
    Location
    Belgium
    Posts
    3,754
    Post Thanks / Like

    Re: DxO lens tets

    I think that's where the crux is Jack. With the Otus there's a drop down list for their tests on different cameras/sensors. For instance on the D750 it scores 24 out of 24.3 MP or 98%, so the score clearly varies with MP count. So comparing numbers between the score on a 36 .6 MP sensor with one on a 45.7 MP sensor is probably not really valid. Unfortunately there's no test of the Nikon 50 on a Z6 that would be roughly comparable to the Otus on a D750.

    Maybe even different AA filters used on the sensors can make a difference, who knows.

    I also see for instance the CZ/Sony 55/1.8 which has a score of 40 on the A7Rii 42 MP sensor (95%). Is it really sharper than the OTUS? I doubt it (even though I have the lens and could kid myself it's the case) but there's no tests on the same sensor to confirm it. And then it gives a score of 29 on the A7R 36 MP sensor (81%) which really doesn't make much sense either.

    So maybe your initial words "IMHO they are flawed..." is closer to the truth than what I initially assumed .
    My Pics
    Likes 1 Member(s) liked this post

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •