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Thread: Does Auto WB correct colour cast from flash modifier ?

  1. #1

    Default Does Auto WB correct colour cast from flash modifier ?

    Few days ago, i used an old stofen diffuser for rim light and end up with an orange cast.

    I took a few photos last night and end up with more questions.


    use grey card, no flash DSC_13633.JPG


    use grey card, then bounce flash with convertible Umbrella (white and black) DSC_13761.JPG


    auto WB, bounce flash with convertible Umbrella (white and black) DSC_1377.JPG


    use grey card, then bounce flash on white card DSC_13941.JPG

    I still like to use my convertible umbrella but i definitely don't want the reddish cast. I think the cast is from the black material of the umbrella. I bounce my flash instead of shoot thru because I hope to retain texture on white material because i believe the black material helps. Is there a better way to flash, perhaps a different modifier ?

    Did auto WB compensate for the reddish cast(DSC_13761.JPG) in DSC_1377.JPG ? DSC_1377.JPG has a bit of cyan cast on my screen.

    When we take WB from a grey card, does flash affect the WB reading ?

    DSC_13941.JPG looks a little bit blue on my screen, but is the best of the four. the white card is only 4A size.

    Any shifu can enlighten me?

  2. #2
    Moderator catchlights's Avatar
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    Default Re: Does Auto WB correct colour cast from flash modifier ?

    shooting flash direct and diffuse will have different color balance.

    the light gone thru or reflect from any material will be affect by the tone of this material, hence the color balance being alter.

    auto WB will judge/measure the light enter the camera color sensor and respond to it, most of the time it will give rather satisfactory results.

    don't quite understand this phrase
    When we take WB from a grey card, does flash affect the WB reading ?
    if you take a WB measuring from a grey card, as in doing a custom WB, you suppose to use the same light source to make subsequent exposure.
    if you plan to do a post WB correction by including a graycard in one of the frame, you also need to use the same light source for all the similar set up.

    Once you change the light source or lighting set up, you need to re-do your custom WB
    Shoot to Live, Live to Shoot
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  3. #3

    Default Re: Does Auto WB correct colour cast from flash modifier ?

    Thanks for your reply. I suppose to re do the WD for DSC_13941.JPG (white card) with flash.

    Normally, when I take a custom WB, I fill up the whole viewfinder with the grey card at front of the subject and take the reading without flash. I should keep the same angle/composition for my shoot later.

    The grey card is used for exposure reading and white balance, can it be used for custom WB with flash ? From your reply earlier, it seems it is possible but my friend thinks otherwise.

    I have no intention to do a Post WB correction by including a grey card in one of the frame.

    quote from above "auto WB will judge/measure the light enter the camera color sensor and respond to it, most of the time it will give rather satisfactory results."

    If auto WB can correct the colour cast from flash modifier, then i dont need to custom WB.
    Last edited by CasualSnaper; 18th June 2010 at 06:26 PM.

  4. #4
    Moderator catchlights's Avatar
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    Default Re: Does Auto WB correct colour cast from flash modifier ?

    Quote Originally Posted by CasualSnaper View Post
    Thanks for your reply. I suppose to re do the WD for DSC_13941.JPG (white card).

    Normally, when I take a custom WB, I fill up the whole viewfinder with the grey card and take the reading without flash.

    My question was "Can I do a custom WB with flash ?"

    I have no intention to do a Post WB correction by including a grey card in one of the frame.

    If auto WB can correct the colour cast from flash modifier, then i dont need to WB.
    same as you do custom WB with ambient light, just fire off with flash.
    Shoot to Live, Live to Shoot
    www.benjaminloo.com | iStock portfolio

  5. #5

    Default Re: Does Auto WB correct colour cast from flash modifier ?

    Catchlights, does the SB iTTL have an Auto WB adjust function that adjusts WB for each shot?

  6. #6
    Moderator catchlights's Avatar
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    Default Re: Does Auto WB correct colour cast from flash modifier ?

    Quote Originally Posted by Dream Merchant View Post
    Catchlights, does the SB iTTL have an Auto WB adjust function that adjusts WB for each shot?
    not sure I able to fully understand what they say, but please read this,

    Nikon Auto exposure and White balance applications
    Highlight analysis: Information from the 1,005-pixel RGB sensor is utilized to precisely detect highlights within the frame. This data is then applied to color matrix metering and i-TTL balanced fill-flash, and the brightness range to be reproduced is calculated to realize more precise exposure control. Light-source identification: Using extracted characteristics information from the 1,005-pixel RGB sensor, the scene is recognized. Correctly identifying the light source ensures more accurate white balance, even in a situation where it is difficult to determine it with conventional auto white balance.

    Auto White Balance from Nikon
    In Nikon D-SLRs, Auto White Balance combines with the Scene Recognition System to analyze each scene’s light sources, cross-referencing this information with 5,000 actual picture data examples from over 20,000 images in the camera's onboard white balance database. Even under mixed lighting or difficult light sources like mercury vapor lights, auto white balance technology calculates an ideal white balance for remarkably faithful colors.
    Scene Recognition System from Nikon




    hope this answer your question.
    Shoot to Live, Live to Shoot
    www.benjaminloo.com | iStock portfolio

  7. #7

    Default Re: Does Auto WB correct colour cast from flash modifier ?

    From what I can gather, yes, it does adjust WB in iTTL but only for fill-flash.

    Thanks.

    Looks like TS has to do custom WB if using flash as main light source.

  8. #8

    Default Re: Does Auto WB correct colour cast from flash modifier ?

    Thanks catchlights on information on the execution and quotations.

    I did the custom WB with flash, and the results are better. I will continue to compare auto WB and custom WB with flash to see which one i prefer.
    Last edited by CasualSnaper; 20th June 2010 at 01:02 PM.

  9. #9

    Default Re: Does Auto WB correct colour cast from flash modifier ?

    I read that before you edited it.

    My idea of 'custom white balance'

    http://www.trygve.com/backslashgel.jpg

  10. #10

    Default Re: Does Auto WB correct colour cast from flash modifier ?

    you win

  11. #11

    Default Re: Does Auto WB correct colour cast from flash modifier ?

    Hi all,

    just a quick noob question, how often do you all use custom white balance?
    i mean to set custom white balance every single time the lighting changes its quite troublesome.

    Will you really be concern over the lighting condition of the picture you took.. as it is hardly noticable for me.

  12. #12

    Default Re: Does Auto WB correct colour cast from flash modifier ?

    Good news to you as it is hardly noticeable differences for you.

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