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Panasonic 25 mm & chromatic aberrations

Discussion in 'Native Lenses' started by SojiOkita, Oct 12, 2014.

  1. SojiOkita

    SojiOkita Mu-43 Top Veteran

    617
    Feb 23, 2014
    France
    Hi everyone,

    I've got my Panasonic 25 mm f/1.4 from a few months now, that I use on my Olympus E-M10.
    I love this lens (that's the lens I use the most since I bought it) except for one thing: I've got a lot of chromatic aberrations on my pictures.
    I've got purple (and green) fringing, mostly when I use wider apertures (so that's nearly all the time as I use mostly wide apertures with this lens).

    That's very annoying to correct: in Lightroom it has to be done manually, and the settings are different for each picture. Most of the times, if you remove the fringe completely, there are some areas on the image (on the skin for example) that are ruined.

    Here are two 1:1 samples.
    The first one is a quite extreme situation but you can see both green & purple fringing:
    im1.

    I observe this on a lot of shots, even some without high contrasts. For example on the second sample there is a fringe tint in the out of focus areas of the image:
    im2.

    I never had such problems with my previous gear.
    With my other lenses, I have some fringing too with the Oly 45 but the phenomenon is a lot more limited.
    I didn't try to compare the rendering on my Olympus & Panasonic bodies yet (I have a GM1 too, but I don't use the PL25 much with the GM1).

    Is there some way to avoid this, or to correct this easily?
    Did some of you switched to the Oly because of this?
     
  2. Ellsass

    Ellsass Mu-43 Regular

    88
    Apr 15, 2014
    Panasonic bodies correct CA automatically and Oly bodies don’t. Have you tried retaking some of those shots with the GM1 to see if they produce a better result?
     
  3. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
    Two types of chromatic aberration. Lateral CA is the kind that is easily corrected and is auto-corrected with some camera/lens combinations. If not corrected automatically by the body it is trivially corrected in Lightroom by checking a box in the lens corrections panel.

    The other kind of CA is Longitudinal CA and this is harder to correct. What you are seeing here is not strictly longitudinal CA since it is in the out of focus areas but it is a similar mechanism with similar problems to correct. No body or automatic procedure is going to help with it. In Lightroom you can use the fringing correction in which you sample the color fringing and/or adjust hue range and amount. You can also locally increase or decrease the effect with brushes or gradients. The degree to which it works depends a lot on the scene.

    Almost all fast lenses do this to some degree, it is a rare lens that does not show some fringing in the out of focus areas. That said the 25/1.4 does do it with some regularity and more so than some other m43 fast primes. There is little you can do to control it if you want to shoot wide open. I don't own it but the 25/1.8 does seem from testing at Lenstip to have a bit less fringing in out of focus areas than the 25/1.4 if that is a primary concern of yours. Lenstip also shows the 45/1.8 to perform well in this regard as your experience suggests.
     
  4. JJJPhoto

    JJJPhoto Mu-43 Veteran

    252
    Jul 8, 2011
    Cincinnati, OH
    Jerry Jackson Jr
    I know exactly what you're talking about with the strong purple/magenta (and sometimes green) color fringing with the Panasonic Leica 25mm lens. I love this lens because of the focal length and the f/1.4 aperture, but I often have to remove the color fringing on high contrast backgrounds (usually where the subject is backlit. Unfortunately, this is characteristic of the way the Leica 25mm renders, so if you don't want to leave it in your shots then you have to learn to process it out.

    There are two ways that I know to do this "relatively" quickly: First, you can buy a copy of Corel PaintShop Pro which has a pretty good one-click purple fringe removal tool. If you want to stick to Adobe, use the lasso tool to select the area with the fringing color. Go to Image > Adjustments > Hue/Saturation. Then where it says "Master" click on the drop down menu and select magenta (or green for green fringe), use the eye dropper tool to select some of the purple/green in the fringing part of your photo, then move the saturation slider down until you can't see it.

    I used the latter solution for this image of my kids (and some other kids) in a swing ride at the Renaissance Festival. The ropes were covered in bright purple fringe prior to editing. The ropes did lose some color, but at least you can't see the purple fringe on the ropes from a mile away. There is also some green fringe around the trees in background, but it's not distracting because at a distance it just blends with the green of the foliage.

    PA120022-X2.
     
  5. SojiOkita

    SojiOkita Mu-43 Top Veteran

    617
    Feb 23, 2014
    France
    I'll make a comparison next weekend but as I never use jpegs, I don't think the correction will apply...
     
  6. SojiOkita

    SojiOkita Mu-43 Top Veteran

    617
    Feb 23, 2014
    France
    I use lightroom for 99.99% of my post processing. I want to stick to raw editing except for special things (i use gimp then).

    I'll see if I find a way to make this work.
    Maybe I'll eventually buy the Oly 25 to make a comparison and sell the one I like less.
     
  7. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
    GM1 CA corrections will pass in metadata to LR in RAW files and LR will automatically apply them. Not sure about the E-M10 RAW path, it corrects on JPGs for sure but I don't know if it and LR handle it properly for RAW files like the GM1 and other Panasonic cameras. And as mentioned earlier, won't help these images at all - this isn't lateral CA and so the CA corrections provided are irrelevant.

    While it can be fussy, do pay attention in LR to the local fringing controls for brush adjustments. This is the best way to handle difficult situations in which aggressive defringing controls are required. You can mask the areas that don't need it or of course do it the other way around as well and just strengthen the areas that do need it.
     
  8. b_rubenstein

    b_rubenstein Mu-43 All-Pro

    Mar 20, 2012
    Melbourne, FL
    Olympus bodies with the TruPic VII processor automatically correct CA in JPG modes regardless of lens brand. I know this because I have an E-M1 & E-M10 that both correct CA and my E-M5 (and E-PL5 & E-PL2 that used to have) that don't.

    I have also have both the Panasonic 25/1.4 & Olympus 25/1.8, and the Olympus has more CA. Just look the lenses up on a lens test site that also measures lateral CA.
     
  9. SojiOkita

    SojiOkita Mu-43 Top Veteran

    617
    Feb 23, 2014
    France
    I made some tests today about purple fringing, on a high contrast subject.

    I tested several lenses on both my E-M10 and my GM1.
    (Oly 45, Panny 14 & 25, and kit lenses)
    I also tested my Canon 40D + some primes (50 & 85) and a zoom (17-55 IS).

    I used different apertures (1.4 - 1.8 - 2.8 - 4.0) and I shot RAW+JPEG to compare the results:
    - all the fringing is visible on both RAW & JPEG (lateral AC are auto corrected but not fringing).
    - there is no sensible difference between the E-M10 & the GM1
    - I didn't see anything noticeable on neither of the zooms. The limited aperture (even on my 17-55 IS which opens at f/2.8) is probably the cause. Same thing on the 14 mm which has a f/2.5 max aperture.
    - The Panasonic 25 mm exhibits a lot of purple fringing at f/1.4. At f/1.8, it is partly gone but still high. At f/2.8 it's hardly noticeable, and at f/4 there is nothing at all.
    - The Oly 45 mm is pretty good. There's hardly any purple fringing at f/1.8.
    - The Canon 50 f/1.4 is by far the lens with the most purple fringing. It's awful at f/1.4, very noticeable at f/1.8, and nearly gone at f/2.8.
    - The Canon 85 f/1.8 is surprisingly good.

    It's not a scientific test... it's probable that in another situation the results would have been different.
    It would have been interesting to compare the Oly & Panny 25, to see if at f/1.8 the Oly is better than the Panasonic.
    But the diffrence would probably not be stunning.

    In fact, the problem is that the Panasonic 25 is fully usable at f/1.4 One third of my shots are at f/1.4, 50% at f/2.0 or wider.
    I have to learn to choose a smaller aperture sometimes when there is a high risk of fringing. (I prefer a little more noise and a less blurred background than purple fringing which is time consuming to correct).
     
  10. SojiOkita

    SojiOkita Mu-43 Top Veteran

    617
    Feb 23, 2014
    France
    Yes, thanks. That's probably the best way to correct fringing when it's there.
     
  11. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Hi, I think you need to edit this and change Oly 25mm to Pana.

    Thanks