Purple fringing with 75mm on E-M5

Discussion in 'Native Lenses' started by rogergu, Dec 14, 2013.

  1. rogergu

    rogergu Mu-43 Regular

    Feb 11, 2013
    Hi all,
    I bought a new 75mm and found obvious purple fringing even on the center of the image. See below 100% crop. Is this normal?

    PC140033.JPG PC140042.JPG
  2. pdk42

    pdk42 One of the "Eh?" team

    Jan 11, 2013
    Leamington Spa, UK
    On really high contrast lines (chrome on cars is a great test case), it does this - as do many other lenses. If you're a LR user, it's fairly easy to clean up though.
  3. LowriderS10

    LowriderS10 Monkey with a camera.

    May 19, 2013
    I wouldn't say that's normal. Considering those are 100% crops and that's pretty much THE hell test for purple fringing, I'd say that combo performs admirably! ;)
  4. Are you shooting everything at f/1.8? Because that will probably do it. I've yet to own a fast prime lens that doesn't have some kind of colour fringing issues at it's wider apertures.
    • Like Like x 1
  5. orfeo

    orfeo Mu-43 Top Veteran

    Sep 27, 2013
    I have a bunch of old fixed FL lenses that have no PF whatsoever. The thing is that they are slower lenses...
    The 35-100mm pana has no purple fringing and no lateral aberration too while the Oly 75mm has both. The 75mm is slightly sharper though, being a fixed FOV you wouldn't expect anything less except for the CA you see here...
  6. rogergu

    rogergu Mu-43 Regular

    Feb 11, 2013
    Yes, both at F/1.8
  7. Amin Sabet

    Amin Sabet Administrator

    Apr 10, 2009
    Boston, MA (USA)
    Yes, it is normal for this lens. It's caused by longitudinal (axial) chromatic aberration (as opposed to lateral CA which would be more pronounced away from the image center). You'll find it on high contrast edges, most often bordering bright highlights. Depending on whether those edges are in front or behind the plane of focus, they may appear purple or green. Generally the color fringing will be absent in the plane of focus, but that can be quite thin at 75mm and f/1.8. If you manually focus on such an edge and use the magnified view, you can see the color change from purple to no color to green as you slowly move the focus point.

    As noted by pdk42, Lightroom makes it easy to clean up in most cases.
  8. rogergu

    rogergu Mu-43 Regular

    Feb 11, 2013
    Thanks for all replies!
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