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random red colour cast in some of my DP2 images

Discussion in 'Sigma DP Forum' started by Tilman Paulin, Aug 3, 2012.

  1. Tilman Paulin

    Tilman Paulin SC Top Veteran

    681
    Nov 15, 2011
    Dublin, Ireland
    Hey everyone,

    I've noticed this for a while now on some of my DP2 photos, in random intervals. Thought I'd probably better ask at some point. :)

    The two attached images have been taken about 30 seconds apart, with the same camera settings, nothing was changed...
    Both were shot with Aperture priority, ISO 200, 1/25 sec, f7.1, -1.3 EV, WB: overcast.

    Yet one of them has a red/magenta cast in the embedded jpeg. (the RAW files seem to be ok)

    I was just wondering if anyone had the same thing happening? Or knows why this happens?
    And if it might be fixed in the newer versions? (DP2x or DP2m) These are from original DP2.
    (It happens to me every once in a while. Not terrible, just a bit annoying sometimes.)

    cheers,
    Tilman

    Extracted jpgs out of the raw-file in SPP:
    [​IMG]
    [​IMG]
     
  2. pdh

    pdh SC Legend

    Jan 2, 2011
    yes, the wonderful world of Foveon colour casts ... this looks magenta rather than red, which I sometimes see in shadow areas from my DP2s; in lowish light in large pale areas I sometimes get a rather fetching green cast.
    you could try desaturating purple in LR or PS . in SPP it's a bit less easy but moving the palette towards yellow might ameliorate it a bit.

    hmm I'm wondering about the -1.3EV though - I leave my DP2s at 0 or +0.3
     
  3. Tilman Paulin

    Tilman Paulin SC Top Veteran

    681
    Nov 15, 2011
    Dublin, Ireland
    This was shot in the evening and I was standing in the shaded area of some trees. I didn't want the camera metering to make the foreground go bright. (I usually have it on Aperture-priority)

    But in case -1.3 Exposure compensation is a bad thing to do on the DP2, shouldn't both images have the same colour cast then?


    It's the randomness and inconsistency that concern me here...
    (I'm also asking because I'd like to find out if the new DPs have similar random inconsistencies in colors...)

    cheers.
    Tilman
     
  4. pdh

    pdh SC Legend

    Jan 2, 2011
    My experience is that inconsistency is a hallmark of the Sigma Foveon.

    We can only hope that the new Merrills are much improved, though I won't be in a position to buy one to find out.

    It might be worth keeping an eye on DPR (if you can stand that) and the Flickr DP1/DP2 and Foveon group discussion threads too.
     
    • Like Like x 1
  5. Tilman Paulin

    Tilman Paulin SC Top Veteran

    681
    Nov 15, 2011
    Dublin, Ireland
    Thanks for the tip with the Flickr group discussion threads! Hadn't thought of those... Will have a look (or two :)
     
  6. snkenai

    snkenai SC All-Pro

    Oct 5, 2010
    kenai, AK
    Stephen Noel
    Never owned a DP, but I do remember the early discussions, emphasizing the need to get the exposure "dead on", or there were serious quality issues.
     
  7. Tilman Paulin

    Tilman Paulin SC Top Veteran

    681
    Nov 15, 2011
    Dublin, Ireland
    I find the exposure metering quite reliable actually. I rarely need to boost exposure much in the RAW conversion.

    I like my images' blacks quite dense though, so I usually have it on -0.7EV in Aperture priority. Maybe that's why I see the problem more often.
    (As it seems to affect mainly dark areas of images...)

    cheers,
    Tilman