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Thread: Color Cast

  1. #1

    Color Cast

    So I picked up an old OM mount Olympus 28mm, it seems like my Pany 25mm has some kind of color cast that is not present in the 28mm. The following images were taken under the same conditions (light and WB) exactly the same; the only difference is the lens used both are shot in Manual mode.

    25mm:

    Color Cast

    28mm:

    Color Cast

    For post processing I used the same spot on the back ground for setting the white balance. Any thoughts on why the color cast is so different in the images?

    Thanks
    Ryo

  2. #2
    Moderator Dave Humphries's Avatar
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    Re: Color Cast

    Hi Ryo,

    To reduce the variables at play here, I would suggest you;
    Take pictures of the same subject
    Set the camera to a fixed WB (that suits the light source)
    Put a larger area of a neutral colored subject in shot if you must color pick the WB in PP

    Depending upon your software and options set, color picking can be a bad idea for WB, especially as I don't see anything obvious in the background to click on that would be reliable, if you do it on too small an area and don't zoom in, you risk getting 10 different results if you're selecting the weave in the material

    Hope that helps,

  3. #3

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    Urban Domeij

    Re: Color Cast

    I am not convinced. There is a light source in the second image, which was not present in the first one. If you look at the reflection of the light source on the release button of the lens mount, as well as reflections over the top of the rounded black surface of the macro lens and compare them to the upper part of the chrome ring of the OM lens in the first image, you can clearly see, that the light source in the first image seems to be mainly windows, while on the Canon macro lens, the main light sources seem to be incandescent, but there is also some reflections of what appears to be daylight.

    To try out if there are differences, you need to use the same lighting, and a test object like the X-rite card would be better.

    Lenses do have different colour filtration, but that is not a problem, as you can always white balance for the lens, either beforehand if you wish to save as jpeg, or after, if you save RAW.

    The problem that is common with older lenses will not be shown as long as you have a dark background, but they become evident if you shoot a dark object in the middle of the image with a bright background, as for example shooting the flat side of a coffee bean on a piece of white paper wit the macro lens. If the AR coating is insufficient, there will be a marked loss of contrast in the center of the image, and you could see it very clearly when shooting a coffee bean in that way against a white backdrop. So called "digital" lenses all have superior AR coating and always deliver crisp contrast, while many old lenses fail that test.

    Colour rendition however is never a problem, not even with the radioactive yellowish lenses that can be cleared in the sun. The cast can always be corrected with white balancing.

  4. #4
    JPS's Avatar
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    Re: Color Cast

    Hi Ryo,
    good advice from Dave here, well worth a try.

    I tried adjusting the WB on your pictures using the the white writing on each lens, as the 'set-point' this adjustment; though not perfect certainly brought both pictures more in-line with each other; ie the colour cast was greatly reduced. I did not adjust any other settings.
    I'll be interested in other people comments.
    Cheers
    John

  5. #5
    Melkus's Avatar
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    Re: Color Cast

    In any case just shoot in RAW and leave the WB set to auto, then in pp set it to what you want

  6. #6

    Re: Color Cast

    I probably should have clarified how I shot these. 1. They were shot with the same in camera WB settings (My M4/3 has 3 customizable presets) Both images were on Custom 1 setting. Both images were shot in RAW, cropped and saved as JPG. The cropped portion is where I set the WB in ACR. (you can see part of the wall in the ULC in frame 2) I didnt think about looking for extra light as Urban had mentioned; as this is an interior office, with no windows, and no way for extra light to get in.... Until I noticed the extra light Urban eluded to...It is from my computer monitors! I will try some test shots with my Monitors off and see how the results turn out!

    Thanks
    Ryo
    Last edited by Ryogenetic; 23rd December 2012 at 09:39 PM.

  7. #7
    Melkus's Avatar
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    Re: Color Cast

    Well we do know that different lenses have different optical qualities and that can impact color shift, contrast, etc so I feel this must be part of your problem.

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