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My Nikon CP5700 manual says to use a white card for white-balance preset. My
wife's CP 3200 manual says to use a gray card. Is this: (1) A difference in
camera operation, (2) Updated thinking since the 3200 is newer, or (3) does
it make any difference? I can see where one camera (5700) might be setting
balance via the highlights while the other might be setting the mid-point
balance. Just curious.

A white card and a grey card have the same color balance....strange but
true!


"Cooter" <> wrote in message
news:hoDBc.64309$. com...
> My Nikon CP5700 manual says to use a white card for white-balance preset.
My
> wife's CP 3200 manual says to use a gray card. Is this: (1) A difference
in
> camera operation, (2) Updated thinking since the 3200 is newer, or (3)
does
> it make any difference? I can see where one camera (5700) might be setting
> balance via the highlights while the other might be setting the mid-point
> balance. Just curious.
>
>

"Gene Palmiter" <> wrote in message
news:SADBc.13279$...
> A white card and a grey card have the same color balance....strange but
> true!

Indeed they can have. When shot upclose, the exposure will be adjusted so
that both will be rendered approx. mid-gray. The only thing to avoid from
there, is fluorescent white.

A gray card produced for the purpose of measuring refectance will probably
be okay on both the white (no smudges) and the gray side. A piece of
ordinary paper may have optical brighteners added, avoid those (if needed
check for fluorescence with a "black light" that emits large amounts of near
UV).

Bart

Ignore that man! White, Grey, and black are NOT colors! The white balance
for all are the same! (ok...don't know what black will do) White balancing
measures the color temperature of the light.....look....its all too much for
a quick post. Go look it up! And Bart...your bit...that is for measuring the
amount of light...not the temp of it.




"Bart van der Wolf" <> wrote in message
news:40d7216b$0$35145$...
>
> "Gene Palmiter" <> wrote in message
> news:SADBc.13279$...
> > A white card and a grey card have the same color balance....strange but
> > true!
>
> Indeed they can have. When shot upclose, the exposure will be adjusted so
> that both will be rendered approx. mid-gray. The only thing to avoid from
> there, is fluorescent white.
>
> A gray card produced for the purpose of measuring refectance will probably
> be okay on both the white (no smudges) and the gray side. A piece of
> ordinary paper may have optical brighteners added, avoid those (if needed
> check for fluorescence with a "black light" that emits large amounts of
near
> UV).
>
> Bart
>

It looks to me like you didn't understand the gist of my post.

Besides, white gray and black ARE colors, but with zero saturation, and they
are supposed to reflect all wavelights of the spectrum with equal intensity
to the incident spectrum's composition. If the reflection adds blue/green
due to fluorecence, the whitebalancing will be off the mark.

Bart

"Gene Palmiter" <> wrote in message
news:5SGBc.16860$...
> Ignore that man! White, Grey, and black are NOT colors! The white balance
> for all are the same! (ok...don't know what black will do) White balancing
> measures the color temperature of the light.....look....its all too much
for
> a quick post. Go look it up! And Bart...your bit...that is for measuring
the
> amount of light...not the temp of it.
>
>
>
>
> "Bart van der Wolf" <> wrote in message
> news:40d7216b$0$35145$...
> >
> > "Gene Palmiter" <> wrote in message
> > news:SADBc.13279$...
> > > A white card and a grey card have the same color balance....strange
but
> > > true!
> >
> > Indeed they can have. When shot upclose, the exposure will be adjusted
so
> > that both will be rendered approx. mid-gray. The only thing to avoid
from
> > there, is fluorescent white.
> >
> > A gray card produced for the purpose of measuring refectance will
probably
> > be okay on both the white (no smudges) and the gray side. A piece of
> > ordinary paper may have optical brighteners added, avoid those (if
needed
> > check for fluorescence with a "black light" that emits large amounts of
> near
> > UV).
> >
> > Bart
> >
>
>

"Bart van der Wolf" <> wrote in message
news:40d763a7$0$35145$...
> It looks to me like you didn't understand the gist of my post.
>
> Besides, white gray and black ARE colors, but with zero saturation, and
they
> are supposed to reflect all wavelights of the spectrum with equal
intensity
> to the incident spectrum's composition. If the reflection adds
blue/green
> due to fluorecence, the whitebalancing will be off the mark.
>
> Bart

Essentially, the more you pay for a grey-card or white-card, the closer
they will be to a true uniform reflection, where all wavelengths of light
are reflected equally. But even the most enpensive vard will not be
perfect, and will therefore have a colour, albeit a colour of a very low
saturation (colour intensity).

What you (the OP) are looking for is uniformity. Whether you are more
likely to get this is a special-purpose photographic card, or in some
"white" paper, is something the group might like to discuss....

Cheers,
David

David J Taylor wrote:

>Essentially, the more you pay for a grey-card or white-card, the closer
>they will be to a true uniform reflection, where all wavelengths of light
>are reflected equally. But even the most enpensive vard will not be
>perfect, and will therefore have a colour, albeit a colour of a very low
>saturation (colour intensity).

I have a minolta A2, and use the white side of a Kodak gray card for
color balance. This works well. However, in very bright sun, the A2
gives an error message. The manual says this is normal, and to use a
gray card for color balance in this situation. I have tried this, and
I don't get the error, but the color rendition is bad (too blue). I
get much better color balance in bright sun using the fixed Daylight
setting than using a custom balance off the gray card. That's an
acceptable solution (for me), but any thoughts for why this might be?

Terry

"Terry" <> wrote in message
news:...
[]
> I have a minolta A2, and use the white side of a Kodak gray card for
> color balance. This works well. However, in very bright sun, the A2
> gives an error message. The manual says this is normal, and to use a
> gray card for color balance in this situation. I have tried this, and
> I don't get the error, but the color rendition is bad (too blue). I
> get much better color balance in bright sun using the fixed Daylight
> setting than using a custom balance off the gray card. That's an
> acceptable solution (for me), but any thoughts for why this might be?
>
> Terry

I once used a Minolta A2, but rejected it in part because the firmware
defects of the A1 had not been fixed in the A2.

It sounds as if the dynamic range of the sensor is limited in bright
sunlight. I have also seen this on other digital cameras (the lens is not
allowed to stop down to a small enough value, because that would cause
diffraction effects to limit the resolution....).

Perhaps your grey card is not as grey as you thought, or perhaps the
Minolta firmware actually can't handle the bright sun situation correctly,
even with a grey rather than a white card? The other classic effect in
bright sunlight conditions is when the scene is exposed just to blue sky,
with no direct sunlight - a north facing scene for example. Is that
causing your problem?

Cheers,
David

David J Taylor wrote:

>"Terry" <> wrote in message
>news:.. .
>[]
>> I have a minolta A2, and use the white side of a Kodak gray card for
>> color balance. This works well. However, in very bright sun, the A2
>> gives an error message. The manual says this is normal, and to use a
>> gray card for color balance in this situation. I have tried this, and
>> I don't get the error, but the color rendition is bad (too blue). I
>> get much better color balance in bright sun using the fixed Daylight
>> setting than using a custom balance off the gray card. That's an
>> acceptable solution (for me), but any thoughts for why this might be?
>
>It sounds as if the dynamic range of the sensor is limited in bright
>sunlight. I have also seen this on other digital cameras (the lens is not
>allowed to stop down to a small enough value, because that would cause
>diffraction effects to limit the resolution....).

No, the camera is exposing things properly in the bright sunlight.
And, as I say, if I select Daylight mode, the color balance is good.

>Perhaps your grey card is not as grey as you thought, or perhaps the
>Minolta firmware actually can't handle the bright sun situation correctly,
>even with a grey rather than a white card?

Could be either of these. I thought the Kodak card would be reliable,
but... And since the camera manual mentioned to use a gray card in
bright light, I thought they would have tested it, but...

>The other classic effect in
>bright sunlight conditions is when the scene is exposed just to blue sky,
>with no direct sunlight - a north facing scene for example. Is that
>causing your problem?

No, happens on all shots, in all directions. And again, it doesn't
happen when you select Daylight setting.

Terry

"Terry" <> wrote in message
news:...
[]
> No, happens on all shots, in all directions. And again, it doesn't
> happen when you select Daylight setting.
>
> Terry

It would be interesting to hear from another A2 owner. I was so disgusted
with mine I sent it back. I did see a firmware update announced recently,
though.

Cheers,
David