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Automatic White Balance
Can someone please explain how Automatic White Balance (AWB) works?
Do most of you use the AWB setting? NM |
#2
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Automatic White Balance
On Wed, 17 Oct 2007 05:25:52 -0700, "~~NoMad~~"
wrote: Can someone please explain how Automatic White Balance (AWB) works? Do most of you use the AWB setting? NM The camera looks at the same scene that you are seeing. Then it averages out all the colors to "guess" at what would be the right white-balance for that scene. Sometimes using the brightest and darkest areas to set white and black points to try to "guess" at what gray must be like. Every camera (and editing program) does it differently. If it detects that every pixel in the scene has an excess amount of blue as an average then it will shift the color balance to yellow to compensate for it. When to use auto white-balance depends on the ambient light source. If I know that all the subjects in the image are going to be bathed in artificial light, then yes. But ONLY if the default settings for tungsten or fluorescent aren't as nice. Those presets will often compensate better than the auto setting. Sometimes using manual white-balance (metering off of a white card under the same light source as your subjects) will be the best of all under unique light-sources or mixed artificial light sources. If on the other hand I want to capture the natural colors of a sunset and not have auto white-balance try to diminish the intense reds, yellows, and golds of the sunset, I will put the camera on daylight setting. I don't want my camera to automatically try to compensate for all those intense warm colors and turn them into pale shades. If I'm under a dense forest canopy where the sunlight filtering through turns everything a shade of green, I look through the breaks in the leaves above to see if that light is coming from full-sun or a cloudy sky, then set the white-balance to the preset of sunlight or cloudy. I don't want the auto white-balance stripping my photos of that natural green hue that's necessary to convey the feeling of being deep in a forest. That's as bad as using flash photography to wipe out the realism in any photo. Since auto white-balance depends on what is in the viewfinder even having your subjects all stand against a colored wall can make their skin-tones shift. Of if they are all wearing the same color of uniform. If that's the case, take it off auto and put it on a white-balance preset or use manual white-balance with a white card. If you use manual white-balance make sure your sample white paper is actually white. Many white papers use a blue tint or fluorescent dyes in them to make them appear whiter under sunlight and its UV content. The same reason that "blueing" used to be sold for doing your white laundry. A blue tint is perceived as whiter by most humans. I just see it as a blue tint. Even many grays contain blue in them to make them appear more gray to the human eye. Auto white-balance can help, but it's not the cure to everything. Often it can harm things more often than you might realize. Sunset photos are often destroyed because people like to keep their camera in auto white-balance mode. That's the most common error that digital camera owners make. Later when viewing their vacation sunset photos they wonder why their pictures don't look as spectacular as what they remembered seeing -- auto white-balance caused that. You still have to know basic photography skills. Only experience and knowing what your camera controls do and won't do will get you an exceptional photo with every shutter press. There is no programmer in the world that can write the proper code in a camera to turn you into a photographer for every situation. Bit-heads know little about real photography and the real world. Just because their algorithm sounds good to them in binary doesn't mean their method is going to work in real life with photography. I know of several forums online inundated with graphic-editing programmers who think they know everything there is to know about photography. (Corel's PSP forums for example.) Yet every one of their edited photos come out looking like total crap. To them, their photos are "mathematically" correct, that's all that they need to know that they must be right. I don't think any of them have even seen a window let alone taken photos in real life. Try to not learn to become dependent on auto modes in your camera, or your editing software. Those auto-routines may have been written by someone who's never left their basement, and most likely were. |
#3
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Automatic White Balance
"TutorialsRus" wrote in message ... On Wed, 17 Oct 2007 05:25:52 -0700, "~~NoMad~~" wrote: Can someone please explain how Automatic White Balance (AWB) works? Do most of you use the AWB setting? NM The camera looks at the same scene that you are seeing. Then it averages out all the colors to "guess" at what would be the right white-balance for that scene. Sometimes using the brightest and darkest areas to set white and black points to try to "guess" at what gray must be like. Every camera (and editing program) does it differently. If it detects that every pixel in the scene has an excess amount of blue as an average then it will shift the color balance to yellow to compensate for it. When to use auto white-balance depends on the ambient light source. If I know that all the subjects in the image are going to be bathed in artificial light, then yes. But ONLY if the default settings for tungsten or fluorescent aren't as nice. Those presets will often compensate better than the auto setting. Sometimes using manual white-balance (metering off of a white card under the same light source as your subjects) will be the best of all under unique light-sources or mixed artificial light sources. If on the other hand I want to capture the natural colors of a sunset and not have auto white-balance try to diminish the intense reds, yellows, and golds of the sunset, I will put the camera on daylight setting. I don't want my camera to automatically try to compensate for all those intense warm colors and turn them into pale shades. If I'm under a dense forest canopy where the sunlight filtering through turns everything a shade of green, I look through the breaks in the leaves above to see if that light is coming from full-sun or a cloudy sky, then set the white-balance to the preset of sunlight or cloudy. I don't want the auto white-balance stripping my photos of that natural green hue that's necessary to convey the feeling of being deep in a forest. That's as bad as using flash photography to wipe out the realism in any photo. Since auto white-balance depends on what is in the viewfinder even having your subjects all stand against a colored wall can make their skin-tones shift. Of if they are all wearing the same color of uniform. If that's the case, take it off auto and put it on a white-balance preset or use manual white-balance with a white card. If you use manual white-balance make sure your sample white paper is actually white. Many white papers use a blue tint or fluorescent dyes in them to make them appear whiter under sunlight and its UV content. The same reason that "blueing" used to be sold for doing your white laundry. A blue tint is perceived as whiter by most humans. I just see it as a blue tint. Even many grays contain blue in them to make them appear more gray to the human eye. Auto white-balance can help, but it's not the cure to everything. Often it can harm things more often than you might realize. Sunset photos are often destroyed because people like to keep their camera in auto white-balance mode. That's the most common error that digital camera owners make. Later when viewing their vacation sunset photos they wonder why their pictures don't look as spectacular as what they remembered seeing -- auto white-balance caused that. You still have to know basic photography skills. Only experience and knowing what your camera controls do and won't do will get you an exceptional photo with every shutter press. There is no programmer in the world that can write the proper code in a camera to turn you into a photographer for every situation. Bit-heads know little about real photography and the real world. Just because their algorithm sounds good to them in binary doesn't mean their method is going to work in real life with photography. I know of several forums online inundated with graphic-editing programmers who think they know everything there is to know about photography. (Corel's PSP forums for example.) Yet every one of their edited photos come out looking like total crap. To them, their photos are "mathematically" correct, that's all that they need to know that they must be right. I don't think any of them have even seen a window let alone taken photos in real life. Try to not learn to become dependent on auto modes in your camera, or your editing software. Those auto-routines may have been written by someone who's never left their basement, and most likely were. Thanks for such an excellent response to my question. My new Canon SX100is has a slew of questionable automatic features and I find that the more I turn them off the better the results get. Thanks, NM |
#4
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Automatic White Balance
In article , ~~NoMad~~
wrote: Can someone please explain how Automatic White Balance (AWB) works? Do most of you use the AWB setting? I do, but then I shoot RAW. In the beginning, I tried matching color balance settings, but the camera thought it was shade when I thought it was cloudy, and so on. With RAW, I don't have mess with nonsense like that. |
#5
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Automatic White Balance
"Mr. Strat" wrote in message ... In article , ~~NoMad~~ wrote: Can someone please explain how Automatic White Balance (AWB) works? Do most of you use the AWB setting? I do, but then I shoot RAW. In the beginning, I tried matching color balance settings, but the camera thought it was shade when I thought it was cloudy, and so on. With RAW, I don't have mess with nonsense like that. Yes, but then of course you have to mess around with nonsense like RAW before you can finish a shot. There is just no free-lunch no matter what you do. NM |
#6
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Automatic White Balance
~~NoMad~~ wrote:
"Mr. Strat" wrote in message ... In article , ~~NoMad~~ wrote: Can someone please explain how Automatic White Balance (AWB) works? Do most of you use the AWB setting? I do, but then I shoot RAW. In the beginning, I tried matching color balance settings, but the camera thought it was shade when I thought it was cloudy, and so on. With RAW, I don't have mess with nonsense like that. Yes, but then of course you have to mess around with nonsense like RAW before you can finish a shot. There is just no free-lunch no matter what you do. No, the shot is taken in the moment. Post processing in RAW can be a breeze if you know what you're doing. To answer your original question, I use AWB almost all the time, shooting RAW or JPEG. I don't use JPEG in situations with tricky lighting, which for me includes most flash situations. -- John McWilliams |
#7
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Automatic White Balance
In article , ~~NoMad~~
wrote: Yes, but then of course you have to mess around with nonsense like RAW before you can finish a shot. There is just no free-lunch no matter what you do. What nonsense? I don't just hold down the button and hope that there's something good in there. I am discriminating and, therefore, don't have to edit many images at a time. I load the image into PhotoShop, bring up the shadow value and (rarely) tweak exposure, sharpen, and save it in whatever format the end use requires. Through my many years in the business, I learned to get it on the negative to begin with. The digital workflow is very minimal. |
#8
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Automatic White Balance
Here an example to add to the excellent TutorialRus's explanation:
http://www.digigrey.com/en_faq.html#camera_wb Cordialement, Jean-Luc Ernst "~~NoMad~~" a écrit dans le message de news: ... Can someone please explain how Automatic White Balance (AWB) works? Do most of you use the AWB setting? NM |
#9
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Automatic White Balance
"~~NoMad~~" wrote in message ... Can someone please explain how Automatic White Balance (AWB) works? Do most of you use the AWB setting? NM OK, I think I figured out the correct procedure for dealing with AWB: I find that the viewing screen on my camera displays an adequate true color representation of the final shot with respect to white balance. It is very easy to flip through the different settings and compare the color balance effect on the screen. Sometimes AWB is OK but not usually. Using the fixed settings for daylight and cloudy seem superior to AWB. Using white card custom white balance feature works best of all as would be expected. NM |
#10
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Automatic White Balance
~~NoMad~~ wrote:
Can someone please explain how Automatic White Balance (AWB) works? Do most of you use the AWB setting? Usually the AWB seems to work on my Canon Powershot A520. But I feel more confident if I choose the Sunny during outdoors sunny conditions and Cloudy during those conditions. Indoors, depending on the illumination, tungsten may work. But I have seen better results with manual white balance using a white sheet of paper when the illumination is a mixture of various source (evening light through the window, florescent, tungsten, etc.). Moreover, sometimes it is worth it to try out the various settings and see what you get on the LCD viewfinder. -HS NM |
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