Curious RAW quirk?

Discussion in 'Digital SLR' started by celcius, Oct 12, 2009.

  1. celcius

    celcius Guest

    Hi all!

    I took in-house photos at a party, setting the WB to flash and using an
    external Canon flash on my Eos 5D MarkII.
    What puzzles me is when I work on the Raw photo in Photoshop CS3 and the
    white balance shows as "as shot", if I change it to "Flash" (which was the
    WB setting on my camera) , I get a cooler temp. Why please this difference?

    Thanks,

    Marcel
     
    celcius, Oct 12, 2009
    #1
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  2. The RAW processor has a different idea of what "Flash" means than does
    the camera!
    How much a difference?
    I generally find that if I leave the WB on auto, it does a superb job on
    85% of my shots. The "auto" function in the processor, though, sometimes
    comes up better than the camera's; sometimes not as good.
     
    John McWilliams, Oct 12, 2009
    #2
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  3. celcius

    Robert Coe Guest

    : Hi all!
    :
    : I took in-house photos at a party, setting the WB to flash and using an
    : external Canon flash on my Eos 5D MarkII.
    : What puzzles me is when I work on the Raw photo in Photoshop CS3 and the
    : white balance shows as "as shot", if I change it to "Flash" (which was the
    : WB setting on my camera), I get a cooler temp. Why please this difference?

    Don't take this as gospel, but I believe it's the case that setting the WB has
    no effect on an EOS Canon in RAW mode. No WB correction is applied; it's left
    entirely up to the post-porcessor. What Photoshop is showing you as "as shot"
    (Canon's own software calls it "shot settings") is merely the camera's
    recommendation of what WB to use in post-processing. It may or may not be what
    you set it to be on the camera.

    JPEG is a different matter. If you tell the camera to use a specific WB
    correction, that's what the camera uses in its conversion of the image to
    JPEG.

    BTW, my impression is that Canon sets the "flash" WB assuming that the flash
    output is colder than even its own flashguns produce in practical use. So if
    you bounce the light off of anything but a pure white reflector, the "flash"
    WB will produce a result that is too red.

    Bob
     
    Robert Coe, Oct 12, 2009
    #3
  4. celcius

    Charles Guest

    Both of the above are correct. Good response.
     
    Charles, Oct 12, 2009
    #4
  5. celcius

    celcius Guest

    Hi Bob!
    I think you've got a point in saying that setting the WB on the camera has
    very little incidence in Raw mode. John says that leaving it on "auto" is
    fine.
    I thought, reading the posts here in the past, that it was always better to
    set the proper WB even when shooting in Raw mode. Now, I'm back to square 1
    ;-)
    Mind you, the beauty here is the fact that being in Raw, everything.. or
    almost is possible.
    Marcel
     
    celcius, Oct 12, 2009
    #5
  6. celcius

    Bob Larter Guest

    That's what I do, & it works for me.
    No, there's no need. The only reason to do so is make the WB on the LCD
    preview look approximately like it will when you process it. Most of the
    time Auto WB does a good enough job.
     
    Bob Larter, Oct 13, 2009
    #6
  7. celcius

    me Guest

    To be precise a copy of the JPEG used for in camera review and the
    histogram(s) is saved within the RAW file it self.
     
    me, Oct 13, 2009
    #7
  8. celcius

    celcius Guest


    Thank you all!
    Since I shoot exclusively in Raw, I've learned something very useful today.
    I used to shoot only in JEPG, but this group and others have convinced me to
    use Raw. This has served me well since I was able to save photos that might
    have been completely wasted otherwise. I find Raw especially useful when I
    shoot with flash and it seems the risk of getting a so so photo is greater.
    Cheers,
    Marcel
     
    celcius, Oct 13, 2009
    #8
  9. celcius

    celcius Guest

    You're absolutely right. Now I understand why I have to post-correct by
    "cooling" the colours or lowering saturation
    Macel
     
    celcius, Oct 13, 2009
    #9
  10. That's plain nuts for those who know what they're doing, and can extract
    far better final images from RAW files than from JPEGs, even when it's
    'perfect' in camera. In such situations, shooting both just wastes time
    and disk space.

    And there are plenty of times for some of us where JPEG alone is good
    enough, and even preferred.
     
    John McWilliams, Oct 13, 2009
    #10
  11. The use I have for JPEGs are mostly when shooting sports in daylight.
    There, rapid bursts may be used, and I am inclined to take many hundreds
    of exposures in a short time, under almost ideal conditions. Most won't
    get printed more than 8 x 10, so I have plenty of decently exposed
    pixels at my disposal. That's the only time I prefer JPEGs, and the only
    time I like RAW plus JPEG is when shooting for B+W.....
     
    John McWilliams, Oct 14, 2009
    #11
  12. celcius

    ColinD Guest

    When shooting RAW, the image data is not influenced by the camera white
    balance setting - but the setting is reported in EXIF and the
    'developing' program takes notice of that setting when processing the
    RAW image. You can override the camera setting to get the image you
    want. The recorded WB is merely a starting point.

    Colin D.
     
    ColinD, Oct 16, 2009
    #12
  13. celcius

    Bob Larter Guest

    With my Canon DSLRs, I find that AutoWB works pretty well 99% of the time.
     
    Bob Larter, Oct 16, 2009
    #13
  14. celcius

    Bob Larter Guest

    <grin> There's always that, isn't there?
     
    Bob Larter, Oct 17, 2009
    #14
  15. celcius

    Robert Coe Guest

    : >I think you've got a point in saying that setting the WB on the camera has
    : >very little incidence in Raw mode. John says that leaving it on "auto" is
    : >fine.
    :
    : WB has no effect on the camera raw data. It is a
    : correction applied only when that data is converted to a
    : JPEG. The camera always generates a JPEG for viewing,
    : which is also used to generate an histogram. But if you
    : don't "shoot JPEG", it is not saved as a file.
    :
    : >I thought, reading the posts here in the past, that it was always better to
    : >set the proper WB even when shooting in Raw mode. Now, I'm back to square 1
    : >;-)
    :
    : Setting WB depends on what you want. It can be, for
    : example, set to provide no correction in order to get an
    : accurate histogram. It can be set to "auto", just to
    : provide Exif data for what the camera calculates as the
    : correct adjustment. ...

    Except that the Exif data don't tell you that. The field just says "Auto". It
    would be nice if the camera told you its determination of the color
    temperature of the ambient light, but my Canons don't.

    Bob
     
    Robert Coe, Oct 17, 2009
    #15
  16. celcius

    Robert Coe Guest

    :
    : > On Mon, 12 Oct 2009 14:56:34 -0800, (Floyd L. Davidson)
    : > wrote:
    : > : >I think you've got a point in saying that setting the WB on the camera
    : > has
    : > : >very little incidence in Raw mode. John says that leaving it on "auto"
    : > is
    : > : >fine.
    :
    : If you have information on what the WB was (e.g. daylight, cloudy, tungsten)
    : and it's applicable to the scene, it's sometimes worth setting, since you
    : may forget what the light was like. Also, there needs to be a "neutral"
    : setting that doesn't change colors. For example, when the subject is a light
    : source (e.g. a sunset sky), white balance doesn't make sense. But that's
    : another rant.
    :
    : > : WB has no effect on the camera raw data. It is a
    : > : correction applied only when that data is converted to a
    : > : JPEG. The camera always generates a JPEG for viewing,
    : > : which is also used to generate an histogram. But if you
    : > : don't "shoot JPEG", it is not saved as a file.
    : > :
    : > : >I thought, reading the posts here in the past, that it was always
    : > better to
    : > : >set the proper WB even when shooting in Raw mode. Now, I'm back to
    : > square 1
    : > : >;-)
    :
    : That's my opinion. Most raw converters will let you change the WB, but
    : setting it can function as a memo of what the light was like. Especially if
    : you do a custom WB measurement.
    :
    : > : Setting WB depends on what you want. It can be, for
    : > : example, set to provide no correction in order to get an
    : > : accurate histogram. It can be set to "auto", just to
    : > : provide Exif data for what the camera calculates as the
    : > : correct adjustment. ...
    : >
    : > Except that the Exif data don't tell you that. The field just says "Auto".
    : > It
    : > would be nice if the camera told you its determination of the color
    : > temperature of the ambient light, but my Canons don't.
    :
    : But DPP might. I think Lightroom will calculate an AWB for you and you can
    : see what it is (and adjust starting from there).

    DPP doesn't. If I'm not happy with the "Auto" WB, and therefore choose the
    "Color Temperature" setting, I'd like it to start with the color temperature
    that it used to produce the auto result. But it doesn't; it always starts at
    5200 degrees K, Canon's idea of daylight. As Floyd Davidson pointed out
    earlier today, the actual color temperature assumption must be encoded in the
    RAW data, and therefore known to DPP, but just try to find it.

    Bob
     
    Robert Coe, Oct 17, 2009
    #16
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