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Rainbow-like reflection?

Discussion in 'Native Lenses' started by fin azvandi, Sep 20, 2012.

  1. fin azvandi

    fin azvandi Mu-43 All-Pro

    Mar 12, 2011
    South Bend, IN
    Can anyone explain what was causing a rainbow-like reflection in some photos I took today with the E-P3 and PL25? I was also shooting with the P20 - all of the PL25 images showed some type of this rainbow-like wavy color, but it doesn't show up in any of the P20 images. Hood on, no polarizer or other filters.

    Here are two examples, cropped to roughly the same FoV.

    PL25_zpsc0e33704.
    Panasonic Leica 25mm f/1.4
    f/4.5, 1/4000, ISO 200

    P20_zps7e7d9ab2.
    Panasonic Lumix 20mm f/1.7
    f/5, 1/4000, ISO 200

    I know I changed relative angles in these two shots, but I have more images from other points around the lot with both lenses and the rainbow effect only happened with (all of) the PL25 shots.
     
  2. Promit

    Promit Mu-43 All-Pro

    Jun 6, 2011
    Baltimore, MD
    Promit Roy
    Looks like moire to me, though I'm surprised it's that visible.
     
    • Like Like x 1
  3. Crdome

    Crdome Mu-43 Hall of Famer

    Sep 11, 2011
    West Central Indiana
    Chrome
    If no one else can help you, get a cheap instant photograph made from it and see if they exists in print form. I think it might be an issue like stripes strangely display on television broadcasts.
     
  4. dhazeghi

    dhazeghi Mu-43 Hall of Famer

    Aug 6, 2010
    San Jose, CA
    Dara
    That's moire. However, in this case it looks like it's caused by your image processing program. Try using a different program to downsample the images (or even just try a different resolution). Moire caused by the camera's sensor/lens is almost never visible on images that are downsampled to 25% or less original size, as your is.

    DH
     
    • Like Like x 2
  5. fin azvandi

    fin azvandi Mu-43 All-Pro

    Mar 12, 2011
    South Bend, IN
    Thanks for the quick replies. FYI, these were shot in RAW and processed in Aperture 3. The patterning is visible in Aperture as well as in exported images (jpg, tiff) at different resolutions. Will try a different RAW converter and report back.

    The surface of the building was obviously several blocks away and it is covered with repeating geometric lines/patterns, I guess with the strong light and viewing from an angle it's creating kind of a "worst case" scenario for moire, and each lens is resolving it differently?
     
  6. dhazeghi

    dhazeghi Mu-43 Hall of Famer

    Aug 6, 2010
    San Jose, CA
    Dara
    Certainly - repeating patterns are the key.

    But I would still bet the problem is with Aperture, not with your files. Moire in your RAW file would require interference being recorded at the pixel level. Outside truly exceptional circumstances, that's simply not going to be visible when the image is shrunk to web resolution.

    DH
     
  7. fin azvandi

    fin azvandi Mu-43 All-Pro

    Mar 12, 2011
    South Bend, IN
    Well, just to follow up I opened the .ORF raw file in a few other programs (DxO, Silkypix, RPP, Olympus Viewer) and the moire is there in all of them - the colors are slightly muted in some compared to others but it's just as clear as in the OP. Go figure.
     
    • Like Like x 1
  8. krugorg

    krugorg Mu-43 Hall of Famer

    Jul 18, 2011
    Minnesota USA
    That's interesting, fin. Okay I guess a weak AA filter and a very sharp lens can do that, but then why wasn't it happening with the 20/1.7? Huh!
     
  9. dhazeghi

    dhazeghi Mu-43 Hall of Famer

    Aug 6, 2010
    San Jose, CA
    Dara
    Magnification. The frequency of the detail and the frequency of the sensor/lens combo have to be very close. So even a slight change in perspective, let alone a change in focal length, can fix it.

    DH
     
    • Like Like x 1