custom white balance/exposure questions ?

Discussion in 'Digital Photography' started by picture taker, Jul 9, 2006.

  1. hi,
    i understand exposure shutter speed,f-stop ,iso etc , shoot with a
    canon 20d ,capture raw files all the time, convert with cs2 and adjust
    the wb if i feel it needs it .
    i have never fully understood whte balance / custom white balance etc

    when people refer to a custom white balance are they trying to make
    everything equal ,meaning the reference of 18% that is often mentioned
    about custom white balance ?.

    say there is a shinny red dress or a white one for that matter and
    they look a lot brighter than the other colors, by doing the custom
    white balance does the camera then read the dresses as the same and
    won't blow out the details ? .

    what is the difference between using a reference card ( gray card ,
    expo disc etc ) to set the custom white balance but ive also heard it
    referd to as usnig it to set the exposure not the white balance ?

    say you are in a gymnasium shooting basketball with an expodisc for you
    to use as reference on the end of the lens pointed at the lights to set
    your custom wb in camera and you crank up the iso does it matter if you
    set the custom wb at a differnt iso than what you will be shooting ?.
    same situation in the same gym ,now your shooting with a flash
    should you just leave the custom set or reshoot the custom wb with the
    expodisc attached while using the flash ?.

    thank you
     
    picture taker, Jul 9, 2006
    #1
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  2. picture taker

    Cooter Guest

    Unless I totally misunderstand your question(s), I think you are confusing
    exposure metering with white balance. ISO should not have any reasonable
    effect on white balance and vice versa. White balance is simply a means of
    setting the camera's response to the prevailing lighting conditions;
    therefore, custom white balance normally refers to setting the camera's
    color response to an existing condition that is different than one of the
    listed white balance settings - Daylight, Incandescent, Flash, etc. Say you
    are shooting in an area illuminated by a mixture of daylight, incandescent
    and fluorescent lighting. Unless you want a particular effect, you would set
    your camera's white balance via the custom (some cameras refer to it as
    'Preset') white balance function.
     
    Cooter, Jul 9, 2006
    #2
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  3. picture taker

    Ben Brugman Guest

    Lets start at an example where the white balance does matter.
    Suppose you do a wedding. The bride clothing is mainly white.

    Lot's of people (especialy the mothers) will complain if the
    dress is not white in the pictures. So if you have a series of
    pictures where the dress is a littlebit green, blue, pink or any
    other shade you have a problem.

    The problem is that in real live the dress takes on the color
    of the lightning which is supplied. For example under cover
    of trees in the grass the dress will turn up a littlebit green.

    In artificial lightning the dress will turn up a bit red.
    (In lightbulbs).

    In the shade on a very clear day the dress will turn up a
    little bit blue.

    With a white dress from the bride this is not acceptable.

    So to prevent the white dress having different colors, you
    have to calibrate calibrate the camera everytime the
    light changes from color. To do that you need a constant
    reference, a white card will work, but a gray card will work
    as well. Working with Raw you can take a picture of the
    gray card and adjust the picture in postprocessing so it
    comes out gray. Working with jpg you can use the graycard
    to set the WB in the camera so the graycard appears gray
    in the jpg file.

    So doing the things correctly the wedding dress appears
    so shade of gray in every picture. Depending on the light
    situation this might be more or less bright, but somewhere
    between white and black and never with a colorcast.
    The exposure offcourse should be correct, but should not
    influence the WB. The mothers will notice a very slight
    color cast on the weddingdress, but wil be less critical
    for the exposure.

    The amount off lightning should not matter to the WB. But
    large changes in the amount of lightning can also mean
    large or small changes in the color of the lightning.
    ISO settings should not influence the WB.

    There are some situations where you can not set the
    WB such that it works for everything in the picture.
    If there are more lightsources, for example incandecent
    and natural light in one scene you can not set the WB
    to both.

    Fluorrecent lightning is a problem as well because
    it isn't a continues spectrum some colors look different
    under this type of light.

    Using a flash requires some thought. Normaly the flash
    will produce light of about 5600 K, this is called the
    color temperature. But if this is combined with available light
    of another color temperature, you have to choose for what
    to go.

    Example of a difficult situation: A bride on the grass (green
    casting) in the sunset (low colortemperature of about 3800 K)
    and using a little flashlight to give some highlights (5600 K).
    Now the underside of the dress will have more green colorcast,
    The main lightning is provided by the sun of 3800 K rather reddisch,
    and the flash which light mainly the front gives you 5600 K. So
    the dress will turn up multicolored which you can not correct with
    WB allone.

    Sory to be this 'long' but I hope this gives you the information
    to work with.

    Ben


    "picture taker" <> schreef in bericht
    news:...
    > hi,
    > i understand exposure shutter speed,f-stop ,iso etc , shoot with a
    > canon 20d ,capture raw files all the time, convert with cs2 and adjust
    > the wb if i feel it needs it .
    > i have never fully understood whte balance / custom white balance etc
    >
    > when people refer to a custom white balance are they trying to make
    > everything equal ,meaning the reference of 18% that is often mentioned
    > about custom white balance ?.
    >
    > say there is a shinny red dress or a white one for that matter and
    > they look a lot brighter than the other colors, by doing the custom
    > white balance does the camera then read the dresses as the same and
    > won't blow out the details ? .
    >
    > what is the difference between using a reference card ( gray card ,
    > expo disc etc ) to set the custom white balance but ive also heard it
    > referd to as usnig it to set the exposure not the white balance ?
    >
    > say you are in a gymnasium shooting basketball with an expodisc for you
    > to use as reference on the end of the lens pointed at the lights to set
    > your custom wb in camera and you crank up the iso does it matter if you
    > set the custom wb at a differnt iso than what you will be shooting ?.
    > same situation in the same gym ,now your shooting with a flash
    > should you just leave the custom set or reshoot the custom wb with the
    > expodisc attached while using the flash ?.
    >
    > thank you
    >
     
    Ben Brugman, Jul 9, 2006
    #3
  4. You seem to be mixed up on the difference between metering for the amount of
    light and metering for the color temperature of the light. If you are just
    moving over from film this is natural...you didn't have to worry about it in
    most cases. Your film was rated for daylight and the printer adjusted it
    from there. If you shot under certain kinds of artificial light such as
    tungsten or florescent you got bad pictures and might not have known why.
    Professionals had special films and filters to adjust for this.

    With digital you don't get other kinds of film so you adjust for the color
    temperature by setting the white balance. You can leave it on automatic and
    let the camera do the best it can. In most cases it will do fine. You have
    to learn of where it goes wrong so you can compensate and set the camera for
    the color temp of the light where you are shooting. Rather than remembering
    the temp of all the types of light you can also set a custom WB by
    registering on a neutral "thing". This thing can be white, gray, maybe even
    black (I have never tried that...but it might work). An 18% card would
    work....and the back of the card is white...an even better choice.

    If you are shooting JPGs you make this choice before you shoot...if you
    shoot RAW you can wait until you get to the computer. Best of all worlds is
    if for each shot you made custom WB and then shoot RAW...but that is too
    much work! As the light temp usually changes slowly you only have to set the
    WB when you suspect the light source changed.

    There is an interesting product that I helped a bit with development that
    overrides the WB. You can see it at www.warmcards.com . These were first
    invented for video where you cannot easily change the color balance after
    you shoot. Using warmcards you can trick your camera into thinking the light
    is too cool (blue) so it makes the shot warmer and gives you nicer skin
    tones and enriches the other colors.

    --
    Thanks,
    Gene Palmiter
    (visit my photo gallery at http://palmiter.dotphoto.com)
    freebridge design group

    "picture taker" <> wrote in message
    news:...
    > hi,
    > i understand exposure shutter speed,f-stop ,iso etc , shoot with a
    > canon 20d ,capture raw files all the time, convert with cs2 and adjust
    > the wb if i feel it needs it .
    > i have never fully understood whte balance / custom white balance etc
    >
    > when people refer to a custom white balance are they trying to make
    > everything equal ,meaning the reference of 18% that is often mentioned
    > about custom white balance ?.
    >
    > say there is a shinny red dress or a white one for that matter and
    > they look a lot brighter than the other colors, by doing the custom
    > white balance does the camera then read the dresses as the same and
    > won't blow out the details ? .
    >
    > what is the difference between using a reference card ( gray card ,
    > expo disc etc ) to set the custom white balance but ive also heard it
    > referd to as usnig it to set the exposure not the white balance ?
    >
    > say you are in a gymnasium shooting basketball with an expodisc for you
    > to use as reference on the end of the lens pointed at the lights to set
    > your custom wb in camera and you crank up the iso does it matter if you
    > set the custom wb at a differnt iso than what you will be shooting ?.
    > same situation in the same gym ,now your shooting with a flash
    > should you just leave the custom set or reshoot the custom wb with the
    > expodisc attached while using the flash ?.
    >
    > thank you
    >
     
    Gene Palmiter, Jul 9, 2006
    #4
  5. picture taker

    Matt Ion Guest

    picture taker wrote:
    > hi,
    > i understand exposure shutter speed,f-stop ,iso etc , shoot with a
    > canon 20d ,capture raw files all the time, convert with cs2 and adjust
    > the wb if i feel it needs it .
    > i have never fully understood whte balance / custom white balance etc


    When you go to the supermarket, you'll notice that they never use
    flourescent lighting over the meat section - this is because flourescent
    typically has a yellowish quality to it, and you don't want your meat
    looking yellow. Instead, they'll use incandescent lights, which have a
    more reddish color, so the meat will look fresh and healthy. Similarly,
    you'll see more flourescent lighting used in the vegetable section,
    especially over green leafy veggies, because it brings out the green more.

    Cameras respond the same way - if you shoot under indoor, incandescent
    lighting, pictures will tend to have a reddish hue; shooting under
    bright sunlight will usually give you the "whitest" light, but shooting
    in the shade will give a "blue" tinge to things... and so on.

    Setting a custom white balance involves giving the camera something
    that's white or light grey to "look" at, something that will reflect all
    colors equally... then "telling" the camera, "Okay, this is what WHITE
    looks like in this lighting".

    White balance is only REALLY applicable when you're shooting JPG and the
    camera is doing internal processing of the picture. When you shoot RAW,
    the camera just stores the data straight from the sensor without
    altering anything. It will include information on the white balance
    setting, that the RAW conversion software can read - this is handy if
    you're using auto white balance or custom white balance, because it
    tells the software what the WB readings were - but the WB setting
    doesn't actually alter the image that comes out of the camera. That
    allows you to correct the WB in software before converting the picture
    to TIF or JPG or whatever format you're going to use.
     
    Matt Ion, Jul 9, 2006
    #5
  6. picture taker wrote:

    > hi,
    > i understand exposure shutter speed,f-stop ,iso etc , shoot with a
    > canon 20d ,capture raw files all the time, convert with cs2 and adjust
    > the wb if i feel it needs it .
    > i have never fully understood whte balance / custom white balance etc
    >
    > when people refer to a custom white balance are they trying to make
    > everything equal ,meaning the reference of 18% that is often mentioned
    > about custom white balance ?.
    >
    > say there is a shinny red dress or a white one for that matter and
    > they look a lot brighter than the other colors, by doing the custom
    > white balance does the camera then read the dresses as the same and
    > won't blow out the details ? .
    >
    > what is the difference between using a reference card ( gray card ,
    > expo disc etc ) to set the custom white balance but ive also heard it
    > referd to as usnig it to set the exposure not the white balance ?
    >
    > say you are in a gymnasium shooting basketball with an expodisc for you
    > to use as reference on the end of the lens pointed at the lights to set
    > your custom wb in camera and you crank up the iso does it matter if you
    > set the custom wb at a differnt iso than what you will be shooting ?.
    > same situation in the same gym ,now your shooting with a flash
    > should you just leave the custom set or reshoot the custom wb with the
    > expodisc attached while using the flash ?.



    Expodisc is OK for setting the white balance, but I would rely on the
    camera's reflected meter for exposure. Yes, white balance should be set
    for flash if you change to flash. I don't believe that chaning ISO
    affects the WB setting.

    Not sure how to set WB with flash using Expodisc. Maybe just put the
    disc on, flash an exposure with a typical subject distance, and use
    that. Would be best if you could have a mostly white area to do it with,
    but experiment.

    Gary Eickmeier
     
    Gary Eickmeier, Jul 10, 2006
    #6
  7. ben, thank you for taking the time to reply ,

    Example of a difficult situation: A bride on the grass (green
    > casting) in the sunset (low colortemperature of about 3800 K)
    > and using a little flashlight to give some highlights (5600 K).
    > Now the underside of the dress will have more green colorcast,
    > The main lightning is provided by the sun of 3800 K rather reddisch,
    > and the flash which light mainly the front gives you 5600 K. So
    > the dress will turn up multicolored which you can not correct with
    > WB allone.
    >

    good example , what would the best way to handle this situation ?


    So to prevent the white dress having different colors, you
    > have to calibrate calibrate the camera everytime the
    > light changes from color. To do that you need a constant
    > reference, a white card will work, but a gray card will work
    > as well. Working with Raw you can take a picture of the
    > gray card and adjust the picture in postprocessing so it
    > comes out gray. Working with jpg you can use the graycard
    > to set the WB in the camera so the graycard appears gray
    > in the jpg file.


    ok everytime the light changes ,time for a new custom wb got it .
    take the 1st picture with a gary card or expodisc click on it on acr
    and save it as you your custom white balance apply it to every image
    shoot under them same lighting conditions , sound right or leave
    camera on awb and use the gray card in acr ?.

    i usually shoot raw with small jpeg ,im thinking it would be better
    to shoot large jpeg along with raw, as it has been said get it right
    when you shoot it , i mostly shoot raw as it seems easier to adjust in
    acr then just crop and sharpen in ps ..
    if the image needs some major adjustments more room to work with a raw
    file than jpeg
    but there is a major difference the way a raw file looks compared to a
    jpeg (when comparing images shot under strobe lights anyhow ,i will
    try large jpeg ,raw later and see )so the custom wb dosen't really
    matter that matter that much

    thank you

    Ben Brugman wrote:
    > Lets start at an example where the white balance does matter.
    > Suppose you do a wedding. The bride clothing is mainly white.
    >
    > Lot's of people (especialy the mothers) will complain if the
    > dress is not white in the pictures. So if you have a series of
    > pictures where the dress is a littlebit green, blue, pink or any
    > other shade you have a problem.
    >
    > The problem is that in real live the dress takes on the color
    > of the lightning which is supplied. For example under cover
    > of trees in the grass the dress will turn up a littlebit green.
    >
    > In artificial lightning the dress will turn up a bit red.
    > (In lightbulbs).
    >
    > In the shade on a very clear day the dress will turn up a
    > little bit blue.
    >
    > With a white dress from the bride this is not acceptable.
    >
    > So to prevent the white dress having different colors, you
    > have to calibrate calibrate the camera everytime the
    > light changes from color. To do that you need a constant
    > reference, a white card will work, but a gray card will work
    > as well. Working with Raw you can take a picture of the
    > gray card and adjust the picture in postprocessing so it
    > comes out gray. Working with jpg you can use the graycard
    > to set the WB in the camera so the graycard appears gray
    > in the jpg file.
    >
    > So doing the things correctly the wedding dress appears
    > so shade of gray in every picture. Depending on the light
    > situation this might be more or less bright, but somewhere
    > between white and black and never with a colorcast.
    > The exposure offcourse should be correct, but should not
    > influence the WB. The mothers will notice a very slight
    > color cast on the weddingdress, but wil be less critical
    > for the exposure.
    >
    > The amount off lightning should not matter to the WB. But
    > large changes in the amount of lightning can also mean
    > large or small changes in the color of the lightning.
    > ISO settings should not influence the WB.
    >
    > There are some situations where you can not set the
    > WB such that it works for everything in the picture.
    > If there are more lightsources, for example incandecent
    > and natural light in one scene you can not set the WB
    > to both.
    >
    > Fluorrecent lightning is a problem as well because
    > it isn't a continues spectrum some colors look different
    > under this type of light.
    >
    > Using a flash requires some thought. Normaly the flash
    > will produce light of about 5600 K, this is called the
    > color temperature. But if this is combined with available light
    > of another color temperature, you have to choose for what
    > to go.
    >
    > Example of a difficult situation: A bride on the grass (green
    > casting) in the sunset (low colortemperature of about 3800 K)
    > and using a little flashlight to give some highlights (5600 K).
    > Now the underside of the dress will have more green colorcast,
    > The main lightning is provided by the sun of 3800 K rather reddisch,
    > and the flash which light mainly the front gives you 5600 K. So
    > the dress will turn up multicolored which you can not correct with
    > WB allone.
    >
    > Sory to be this 'long' but I hope this gives you the information
    > to work with.
    >
    > Ben
    >
    >
     
    picture taker, Jul 10, 2006
    #7
  8. gene, thank you for the reply.


    say for example you are shooting a bride /groom and there party under
    the same lighting condition you did a CUSTOM WB for ,say out side in
    the shade and you are using your flash for fill .wouldn't it be easier
    to just shoot raw if they happended to want a larger print and if by
    chance there was something you hadn't noticed and had to do some
    seriuos corrections to ,working with a raw file would be alot easier
    right ?
    or to really do it right you would need to do a custom wb for every
    shot amd lords knows on a wedding day you don't have the timne for that


    thank you


    Gene Palmiter wrote:


    > If you are shooting JPGs you make this choice before you shoot...if you
    > shoot RAW you can wait until you get to the computer. Best of all worlds is
    > if for each shot you made custom WB and then shoot RAW...but that is too
    > much work! As the light temp usually changes slowly you only have to set the
    > WB when you suspect the light source changed.
    >
    > There is an interesting product that I helped a bit with development that
    > overrides the WB. You can see it at www.warmcards.com . These were first
    > invented for video where you cannot easily change the color balance after
    > you shoot. Using warmcards you can trick your camera into thinking the light
    > is too cool (blue) so it makes the shot warmer and gives you nicer skin
    > tones and enriches the other colors.
    >
    > --
    > Thanks,
    > Gene Palmiter
    > (visit my photo gallery at http://palmiter.dotphoto.com)
    > freebridge design group
    >
    > "picture taker" <> wrote in message
    > news:...
    > > hi,
    > > i understand exposure shutter speed,f-stop ,iso etc , shoot with a
    > > canon 20d ,capture raw files all the time, convert with cs2 and adjust
    > > the wb if i feel it needs it .
    > > i have never fully understood whte balance / custom white balance etc
    > >
    > > when people refer to a custom white balance are they trying to make
    > > everything equal ,meaning the reference of 18% that is often mentioned
    > > about custom white balance ?.
    > >
    > > say there is a shinny red dress or a white one for that matter and
    > > they look a lot brighter than the other colors, by doing the custom
    > > white balance does the camera then read the dresses as the same and
    > > won't blow out the details ? .
    > >
    > > what is the difference between using a reference card ( gray card ,
    > > expo disc etc ) to set the custom white balance but ive also heard it
    > > referd to as usnig it to set the exposure not the white balance ?
    > >
    > > say you are in a gymnasium shooting basketball with an expodisc for you
    > > to use as reference on the end of the lens pointed at the lights to set
    > > your custom wb in camera and you crank up the iso does it matter if you
    > > set the custom wb at a differnt iso than what you will be shooting ?.
    > > same situation in the same gym ,now your shooting with a flash
    > > should you just leave the custom set or reshoot the custom wb with the
    > > expodisc attached while using the flash ?.
    > >
    > > thank you
    > >
     
    picture taker, Jul 10, 2006
    #8
  9. couter thanks for the reply .

    i understand exposure but had seen pepole refer to using a gary card
    instead of a CUSTOM TOOL for white balance i using it for exposure
    setting ..

    thanks


    Cooter wrote:
    > Unless I totally misunderstand your question(s), I think you are confusing
    > exposure metering with white balance. ISO should not have any reasonable
    > effect on white balance and vice versa. White balance is simply a means of
    > setting the camera's response to the prevailing lighting conditions;
    > therefore, custom white balance normally refers to setting the camera's
    > color response to an existing condition that is different than one of the
    > listed white balance settings - Daylight, Incandescent, Flash, etc. Say you
    > are shooting in an area illuminated by a mixture of daylight, incandescent
    > and fluorescent lighting. Unless you want a particular effect, you would set
    > your camera's white balance via the custom (some cameras refer to it as
    > 'Preset') white balance function.
     
    picture taker, Jul 10, 2006
    #9
  10. matt, thank you for the reply,
    ill be looking at the lights in the supermarket next time im there lol
    , makes alot of sense
    so you don't think it really matters if shooting raw to do a custom WB
    or not if shooting raw ?
    the hardest challenge for me is to be able to capture a black tux and
    white gown with out blowing the highlights or underexposing the black.
    thanks.

    Matt Ion wrote:
    > When you go to the supermarket, you'll notice that they never use
    > flourescent lighting over the meat section - this is because flourescent
    > typically has a yellowish quality to it, and you don't want your meat
    > looking yellow. Instead, they'll use incandescent lights, which have a
    > more reddish color, so the meat will look fresh and healthy. Similarly,
    > you'll see more flourescent lighting used in the vegetable section,
    > especially over green leafy veggies, because it brings out the green more.
    >
    > Cameras respond the same way - if you shoot under indoor, incandescent
    > lighting, pictures will tend to have a reddish hue; shooting under
    > bright sunlight will usually give you the "whitest" light, but shooting
    > in the shade will give a "blue" tinge to things... and so on.
    >
    > Setting a custom white balance involves giving the camera something
    > that's white or light grey to "look" at, something that will reflect all
    > colors equally... then "telling" the camera, "Okay, this is what WHITE
    > looks like in this lighting".
    >
    > White balance is only REALLY applicable when you're shooting JPG and the
    > camera is doing internal processing of the picture. When you shoot RAW,
    > the camera just stores the data straight from the sensor without
    > altering anything. It will include information on the white balance
    > setting, that the RAW conversion software can read - this is handy if
    > you're using auto white balance or custom white balance, because it
    > tells the software what the WB readings were - but the WB setting
    > doesn't actually alter the image that comes out of the camera. That
    > allows you to correct the WB in software before converting the picture
    > to TIF or JPG or whatever format you're going to use.
     
    picture taker, Jul 10, 2006
    #10
  11. gary, thanks for the reply,
    ill have to experment,
    thank you

    Gary Eickmeier wrote:
    >
    > Not sure how to set WB with flash using Expodisc. Maybe just put the
    > disc on, flash an exposure with a typical subject distance, and use
    > that. Would be best if you could have a mostly white area to do it with,
    > but experiment.
    >
     
    picture taker, Jul 10, 2006
    #11
  12. picture taker wrote:
    > gary, thanks for the reply,
    > ill have to experment,
    > thank you
    >
    > Gary Eickmeier wrote:
    >
    >>Not sure how to set WB with flash using Expodisc. Maybe just put the
    >>disc on, flash an exposure with a typical subject distance, and use
    >>that. Would be best if you could have a mostly white area to do it with,
    >>but experiment.


    I think the book said something about shooting into a mirror, but that
    would only give you the WB for the flash, not the total lighting
    situation. My Oly E20 can do WB with flash by aiming at a white surface.
    Only difference would be put the disc on the lens first.

    Gary Eickmeier
     
    Gary Eickmeier, Jul 11, 2006
    #12
  13. picture taker

    Guest

    If you are shooting raw and do a custom wb then your histogram will be
    more accurate because the colors will line up on top of each other and
    be less likely to clip. If you camera does not have a three channel
    histogram it will show no clipping until you get a chance to look at it
    in post.


    picture taker wrote:
    > hi,
    > i understand exposure shutter speed,f-stop ,iso etc , shoot with a
    > canon 20d ,capture raw files all the time, convert with cs2 and adjust
    > the wb if i feel it needs it .
    > i have never fully understood whte balance / custom white balance etc
    >
    > when people refer to a custom white balance are they trying to make
    > everything equal ,meaning the reference of 18% that is often mentioned
    > about custom white balance ?.
    >
    > say there is a shinny red dress or a white one for that matter and
    > they look a lot brighter than the other colors, by doing the custom
    > white balance does the camera then read the dresses as the same and
    > won't blow out the details ? .
    >
    > what is the difference between using a reference card ( gray card ,
    > expo disc etc ) to set the custom white balance but ive also heard it
    > referd to as usnig it to set the exposure not the white balance ?
    >
    > say you are in a gymnasium shooting basketball with an expodisc for you
    > to use as reference on the end of the lens pointed at the lights to set
    > your custom wb in camera and you crank up the iso does it matter if you
    > set the custom wb at a differnt iso than what you will be shooting ?.
    > same situation in the same gym ,now your shooting with a flash
    > should you just leave the custom set or reshoot the custom wb with the
    > expodisc attached while using the flash ?.
    >
    > thank you
     
    , Jul 11, 2006
    #13
  14. ron, thanks for the reply,
    im using a canon 20d
    does it make a difference if you have the image size set to raw & jpeg
    while dong a custom white balance , or better to put on joeg then
    change your image quality to raw and jpeg ?
    im thinking not but figured i would ask .

    thank you

    wrote:
    > If you are shooting raw and do a custom wb then your histogram will be
    > more accurate because the colors will line up on top of each other and
    > be less likely to clip. If you camera does not have a three channel
    > histogram it will show no clipping until you get a chance to look at it
    > in post.
    >
    >
    > picture taker wrote:
    > > hi,
    > > i understand exposure shutter speed,f-stop ,iso etc , shoot with a
    > > canon 20d ,capture raw files all the time, convert with cs2 and adjust
    > > the wb if i feel it needs it .
    > > i have never fully understood whte balance / custom white balance etc
    > >
    > > when people refer to a custom white balance are they trying to make
    > > everything equal ,meaning the reference of 18% that is often mentioned
    > > about custom white balance ?.
    > >
    > > say there is a shinny red dress or a white one for that matter and
    > > they look a lot brighter than the other colors, by doing the custom
    > > white balance does the camera then read the dresses as the same and
    > > won't blow out the details ? .
    > >
    > > what is the difference between using a reference card ( gray card ,
    > > expo disc etc ) to set the custom white balance but ive also heard it
    > > referd to as usnig it to set the exposure not the white balance ?
    > >
    > > say you are in a gymnasium shooting basketball with an expodisc for you
    > > to use as reference on the end of the lens pointed at the lights to set
    > > your custom wb in camera and you crank up the iso does it matter if you
    > > set the custom wb at a differnt iso than what you will be shooting ?.
    > > same situation in the same gym ,now your shooting with a flash
    > > should you just leave the custom set or reshoot the custom wb with the
    > > expodisc attached while using the flash ?.
    > >
    > > thank you
     
    picture taker, Jul 11, 2006
    #14
  15. picture taker

    Matt Ion Guest

    picture taker wrote:
    > matt, thank you for the reply,
    > ill be looking at the lights in the supermarket next time im there lol
    > , makes alot of sense


    :)

    > so you don't think it really matters if shooting raw to do a custom WB
    > or not if shooting raw ?


    Like I said, it WILL embed the WB information in the file, so the RAW
    conversion software knows where to start and make life a bit easier, and
    if you've set a custom WB, it will avoid needing to guess at it later...
    but no, it's not necessary.

    Note that most cameras do have the option to embed a JPG in the RAW file
    as well, and many viewers will just pull up that JPG for a quick view;
    also, some cameras (Canons at least) store a separate .THM "thumbnail"
    file, which is also a small JPG... the WB setting WILL affect the look
    of these files. If you're processing the RAW, it won't matter, but the
    thumbnails and/or quick views may look "off".

    > the hardest challenge for me is to be able to capture a black tux and
    > white gown with out blowing the highlights or underexposing the black.
    > thanks.


    I know what you mean - we have a "tuxedo" cat (all black and white) and
    taking a good picture of her is a PITA. Having the extra dynamic range
    of RAW can certainly be helpful.
     
    Matt Ion, Jul 11, 2006
    #15
  16. picture taker

    Guest

    hmm, good question. I do not know. I have not tried shooting jpg's of
    any kind. My guess is that a jpg for purposes of wbing would be the
    equivalent to a raw for the same purpose. The question is more than
    academic from the standpoint that a photographer could pre-shoot the
    custom wb images for wedding, for example, then quickly set them as
    needed. Having the wb images as small files would save a lot of
    memory. Conceivably you could get an entire wedding on a single 4GB
    card. Hopefully one of the smart photographers will chime in here with
    an answer.

    Good luck,
    Ron

    picture taker wrote:
    > ron, thanks for the reply,
    > im using a canon 20d
    > does it make a difference if you have the image size set to raw & jpeg
    > while dong a custom white balance , or better to put on joeg then
    > change your image quality to raw and jpeg ?
    > im thinking not but figured i would ask .
    >
    > thank you
    >
    > wrote:
    > > If you are shooting raw and do a custom wb then your histogram will be
    > > more accurate because the colors will line up on top of each other and
    > > be less likely to clip. If you camera does not have a three channel
    > > histogram it will show no clipping until you get a chance to look at it
    > > in post.
    > >
    > >
    > > picture taker wrote:
    > > > hi,
    > > > i understand exposure shutter speed,f-stop ,iso etc , shoot with a
    > > > canon 20d ,capture raw files all the time, convert with cs2 and adjust
    > > > the wb if i feel it needs it .
    > > > i have never fully understood whte balance / custom white balance etc
    > > >
    > > > when people refer to a custom white balance are they trying to make
    > > > everything equal ,meaning the reference of 18% that is often mentioned
    > > > about custom white balance ?.
    > > >
    > > > say there is a shinny red dress or a white one for that matter and
    > > > they look a lot brighter than the other colors, by doing the custom
    > > > white balance does the camera then read the dresses as the same and
    > > > won't blow out the details ? .
    > > >
    > > > what is the difference between using a reference card ( gray card ,
    > > > expo disc etc ) to set the custom white balance but ive also heard it
    > > > referd to as usnig it to set the exposure not the white balance ?
    > > >
    > > > say you are in a gymnasium shooting basketball with an expodisc for you
    > > > to use as reference on the end of the lens pointed at the lights to set
    > > > your custom wb in camera and you crank up the iso does it matter if you
    > > > set the custom wb at a differnt iso than what you will be shooting ?.
    > > > same situation in the same gym ,now your shooting with a flash
    > > > should you just leave the custom set or reshoot the custom wb with the
    > > > expodisc attached while using the flash ?.
    > > >
    > > > thank you
     
    , Jul 11, 2006
    #16
  17. picture taker

    Ben Brugman Guest

    <> schreef in bericht
    news:...
    > If you are shooting raw and do a custom wb then your histogram will be
    > more accurate because the colors will line up on top of each other and
    > be less likely to clip. If you camera does not have a three channel
    > histogram it will show no clipping until you get a chance to look at it
    > in post.
    >

    White balancing is done after the raw is made. So it does not
    influence the Raw's histogram.

    Your suggestion would only have an advantage if the colors
    in the picture would line up. For most pictures this is not
    the case. For pictures where clipping occurs in one channel
    it is most often because that color is more dominant.

    ben
     
    Ben Brugman, Jul 12, 2006
    #17
  18. picture taker

    Guest

    Hi Ben,
    Are you sure? It seems to me that I have far less single channel
    clipping when I do a custom wb. I would not have mentioned it if I had
    not done testing. I am convinced I get a more accurate histogram on my
    Canon 300d if I do a custom wb.

    Thanks,
    Ron


    Ben Brugman wrote:
    > <> schreef in bericht
    > news:...
    > > If you are shooting raw and do a custom wb then your histogram will be
    > > more accurate because the colors will line up on top of each other and
    > > be less likely to clip. If you camera does not have a three channel
    > > histogram it will show no clipping until you get a chance to look at it
    > > in post.
    > >

    > White balancing is done after the raw is made. So it does not
    > influence the Raw's histogram.
    >
    > Your suggestion would only have an advantage if the colors
    > in the picture would line up. For most pictures this is not
    > the case. For pictures where clipping occurs in one channel
    > it is most often because that color is more dominant.
    >
    > ben
     
    , Jul 12, 2006
    #18
  19. picture taker

    Ben Brugman Guest

    <> schreef in bericht
    news:...
    > Hi Ben,
    > Are you sure? It seems to me that I have far less single channel
    > clipping when I do a custom wb. I would not have mentioned it if I had
    > not done testing. I am convinced I get a more accurate histogram on my
    > Canon 300d if I do a custom wb.


    I do not know for the 300d, but from what you write I suspect that
    the histogram is derived from an internal or external jpeg.

    After digitization of the data from the sensor the data is only
    compressed (lossless or losy) and some header information
    is added. The individual values of the subpixels are not altered.


    Other not likely scenario's.
    On your Canon 300d some processing is done on the RAW file
    influenced by the WB settings.
    The white balance setting influences the Exposure.
    The white balance setting influences the DA convertor.

    (All three seem extremely unlikely to me, but I do not have a
    300d and have not tested the 300d).

    ben


    >
    > Thanks,
    > Ron
    >
    >
    > Ben Brugman wrote:
    >> <> schreef in bericht
    >> news:...
    >> > If you are shooting raw and do a custom wb then your histogram will be
    >> > more accurate because the colors will line up on top of each other and
    >> > be less likely to clip. If you camera does not have a three channel
    >> > histogram it will show no clipping until you get a chance to look at it
    >> > in post.
    >> >

    >> White balancing is done after the raw is made. So it does not
    >> influence the Raw's histogram.
    >>
    >> Your suggestion would only have an advantage if the colors
    >> in the picture would line up. For most pictures this is not
    >> the case. For pictures where clipping occurs in one channel
    >> it is most often because that color is more dominant.
    >>
    >> ben

    >
     
    Ben Brugman, Jul 12, 2006
    #19
  20. picture taker

    Guest

    Thank you for not dismissing my opinion out of hand. Recently I
    photographed a bright orange flower on a high key background using
    tungsten halogen. The first three exposures I adjusted only the
    aperture (because this was a very deep flower). Then I realized I had
    forgot to do a custom wb. So I did the custom wb then re-shot with the
    same settings. In each case i kept the information about a third stop
    from the right side of the histogram. After examining each image in
    post I had dramatic clipping on one channel all three precustom wb and
    no clipping after custom wb. Admittedly this was a test with a
    dominant color but I have had similar results with a turtle in tall
    grass and other subjects. Does this seem like a valid test? My guess
    is that the custom wb only has an influence on the way the histogram is
    displayed but your scenarios are definite possibilities. I would like
    to know what is going on.

    Thanks for the reply,
    Ron


    Ben Brugman wrote:
    > <> schreef in bericht
    > news:...
    > > Hi Ben,
    > > Are you sure? It seems to me that I have far less single channel
    > > clipping when I do a custom wb. I would not have mentioned it if I had
    > > not done testing. I am convinced I get a more accurate histogram on my
    > > Canon 300d if I do a custom wb.

    >
    > I do not know for the 300d, but from what you write I suspect that
    > the histogram is derived from an internal or external jpeg.
    >
    > After digitization of the data from the sensor the data is only
    > compressed (lossless or losy) and some header information
    > is added. The individual values of the subpixels are not altered.
    >
    >
    > Other not likely scenario's.
    > On your Canon 300d some processing is done on the RAW file
    > influenced by the WB settings.
    > The white balance setting influences the Exposure.
    > The white balance setting influences the DA convertor.
    >
    > (All three seem extremely unlikely to me, but I do not have a
    > 300d and have not tested the 300d).
    >
    > ben
    >
    >
    > >
    > > Thanks,
    > > Ron
    > >
    > >
    > > Ben Brugman wrote:
    > >> <> schreef in bericht
    > >> news:...
    > >> > If you are shooting raw and do a custom wb then your histogram will be
    > >> > more accurate because the colors will line up on top of each other and
    > >> > be less likely to clip. If you camera does not have a three channel
    > >> > histogram it will show no clipping until you get a chance to look at it
    > >> > in post.
    > >> >
    > >> White balancing is done after the raw is made. So it does not
    > >> influence the Raw's histogram.
    > >>
    > >> Your suggestion would only have an advantage if the colors
    > >> in the picture would line up. For most pictures this is not
    > >> the case. For pictures where clipping occurs in one channel
    > >> it is most often because that color is more dominant.
    > >>
    > >> ben

    > >
     
    , Jul 12, 2006
    #20
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