Automatic White Balance
 

Can someone please explain how Automatic White Balance (AWB) works?

Do most of you use the AWB setting?


NM

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.

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

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.

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

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

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.

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

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

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