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E-PL1 White Balance

Discussion in 'Olympus Cameras' started by MajorMagee, Jan 28, 2012.

  1. MajorMagee

    MajorMagee Mu-43 All-Pro

    Feb 24, 2011
    Dayton, OH
    I've just completed a WB Calibration Study with my E-PL1. What got me started on this was reading about traditional lens filters and I realized that the digital camera WB settings were really just applying color correction as you might do post-process in Photoshop.

    Traditional filters were developed to shift the color of the incoming light warmer or cooler so that the daylight color balanced film could produce neutral colors under varying conditions. Digital sensors are similarly set to record neutral colors at nearly the same temperature light as 5,500K daylight balanced film. In the E-PL1 Daylight WB is set for 5,300K, and the Built In Flash WB is 5,500K.

    So today at noon I took a series of shots of the white standard I use for setting One Touch White Balance to see how the various WB presets are done. What I ended up with is a series of solid color hues that are what the camera thinks will neutralize the light associated with each setting.

    For example, the light really was neutral so when I applied the Tungsten Setting the camera thought it needed to make the light bluer to shift the image to a neutral shade. I was able to capture a shot of a cool blue that is equivalent to the lens filter needed for Daylight Film if you were shooting inside with Incandescent lighting. The validation of this approach was that the Daylight, Auto and One Touch White Balance all produced a nearly neutral shade under the sunny noon conditions.

    I used the Photoshop color picker to check the hue from HSB, and the a and b values from LAB to get a measure of the shades the camera was applying to the image.

    Setting, Temperature, Hue#, a#, b#

    CWB, 2000K, 210, 8, -66 (Lower Range Limit)
    Tungsten, 3000K, 206, -10, -44
    Fluorescent 1, 4000k, 227, 3, -21
    Fluorescent 2, 4500K, 231, 3, -16
    One Touch, Noon, 248, 1, -1
    Daylight, 5300K, 262, 1, -1
    Auto, Noon Light, 310, 1, -1
    Flash, 5500K, 25, 4, 7
    Cloudy, 6000K, 26, 3, 5
    Fluorescent 3, 6600K, 354, 9, 2
    Shadows, 7500K, 33, 5, 16
    CWB, 14000K, 39, 9, 40 (Upper Range Limit)

    The readings that didn't actually need correcting for noon sunlight were nearly neutral so the Photoshop Hue values for those seem to be somewhat arbitrary. The others clearly run blue for low temperatures to shift them higher, and amber for high temperatures to shift them cooler. The one odd one was at 6600k that had a somewhat out of place distinctly mauve shade to it.

    Nothing too earth shattering here, but if you don't want to carry around color lens filters, you can still do some special effects by using inappropriate WB settings to simulate them. Let's say you're shooting with nice neutral noon lighting but you want to cool the image then setting the WB to Tungsten (lower temp) will provide a false blue color tint. Want to warm things up, set it to Shade (higher temp), to add some nice amber tones.
     
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  2. FastCorner

    FastCorner Mu-43 Veteran

    310
    May 28, 2011
    Agree :)

    P1040049-lr3-edit.

    P1040052-lr3-edit.

    P1040053-lr3-edit.

    From Taiwan's recycled plastic bottle building
     
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  3. rex87

    rex87 Mu-43 Regular

    192
    Jun 21, 2011
    winnipeg, mb
    thanks for the info Magee..very usefull