white balance vs, gray card

[HendrikG]

[ QUOTE ]
By the way, if you use a gray card to do the white balance you will not get the same results as using a white card. Virtually every digital camera guide specifies doing the custom white balance with a white card. Now perhaps that is because a white card is always white and gray cards vary so much (13% to 18%).
Cheers,
rfs


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Hi RFS,

I'm sorry I don't agree with you. The WB is only a way of telling the camera 'This measurement is neutral'. If the camera could measure the target, you could even use a blackcard (you can’t of course).

The danger with a white card is the change to overexpose, that in turn will lead to slight colorcasts.

I always use a greycard to get the WB and a flashmeter to determine the correct exposure. This combo works for me. White is white when I measure it in PS.

[R_Fredrick_Smith]

To each, his own! [img]/ubbthreads/images/graemlins/smile.gif[/img]

One may logically ask, though, why many major makers of digital cameras say in the user's guide to do the white balance using a white card. This also seems to hold true for video cameras.

Here is a reference of interest on this subject:

http://www.luminous-landscape.com/tu.../dig-exp.shtml

Cheers,
rfs

[danbritt]

Yes, it does have a magenta cast.
This shot was originally taken on Kodak Portra NC 400 film.

7 days before the session,
I metered it by shooting a test roll of Kodak Portra NC 400 film,
one strobe light set at a certain power, 8 feet away,
a white umbrella as the light modifier.
With the shutter speed at 1/60, I took a photo at every F stop.
It was a heavy experiment on film speed, distance, and light.
I took the images to a lab that knew what they were doing and
discussed which was the best negative for a print.

Well any way...it was a good print.

I like to hear every opinion,
take my camera and shoot.

What works for me... I remember.
What does not work... I toss.

I shoot film, with a Minolta Spot meter,
gray cards, lights and light modifiers.

I reckon this is what photographer’s
should do, regardless of format.
Listen, try, learn, experiment.
Learn for your self what works.
Use what works for you !

The real B in photography is getting out of the studio,
and into real light.

Tom Snyder (DanBritt)

[HendrikG]

[ QUOTE ]
To each, his own! [img]/ubbthreads/images/graemlins/smile.gif[/img]


[/ QUOTE ]

You are right.

I know this is an old discussion (white card versus gray card). Because it’s an old discussion and still going on, one must conclude that the differences are marginal, otherwise one method would have been chosen as the standard. [img]/ubbthreads/images/graemlins/laugh.gif[/img]

I’m familiar with the article. One remark he failed to mention: A Kodak Gray Card is 18% gray. A correct expose is with the peak just left of the center. The reason is that meters a calibrated to the ANSI standard 12% gray.

Greetings,
Hendrik

[Gregor]

Interesting post.

As someone who doesnt rely on in camera metering, I think that there is not only a debate about White Balance but ISOs with digital cameras.

Is it as futile to try to use an ambient meter with an X,Y or Z b r a n d of digital camera to determine exposure as it is to use a gray card?

Is it simply better to use the LCD or a connected laptop to determine the colour?

There are seemingly infinitely variable settings for white balance which makes me wonder why I am so worried about getting a digital camera that will allow me more accurate WB settings than one that does not. There seemed to be a standard with ISO and film (of course you push and pull for effect) but the graph for the film was standard (in any given processing solution).

What are the equivalent standards for digital bodies? ISO and White Balance.