White Balance ?

[Dean Humphrey]

Everyone, I consider myself an advansed DSLR user with still plenty to learn. I have a question about the use of a white balance card. My good friend who shoots Nikon and Fuji uses a gray card to set his white balance. Is it acceptable for Canon users to also use this or is it a must to use white?
Your help and advice is appreciated.
Thank
Dean
Yukon Ok.

[FlyingPhotog]

So long as your target is equal in R G B values, you can use it to white balance.

255, 255, 255
70, 70, 70
0, 0, 0

Will all give the same result.

[Dean Humphrey]

So long as your target is equal in R G B values, you can use it to white balance.

255, 255, 255
70, 70, 70
0, 0, 0

Will all give the same result.


Sorry to say that goes right over my head, I know the numbers represent a color number but I do not understand exactly what you mean. Is that a setting in my camera?
Thanks

[tonylong]

Sorry to say that goes right over my head, I know the numbers represent a color number but I do not understand exactly what you mean. Is that a setting in my camera?
Thanks

The numbers just represent relative color values: pure white is fully saturated values for Red, Green and Blue (255, 255, 255 on the "digital scale").

White balance is set using a "neutral" color, so you could use pure white as above or any other "shade of gray" that is neutral such as a gray card (which would have equal "numbers" for R, G and B).

[Dean Humphrey]

The numbers just represent relative color values: pure white is fully saturated values for Red, Green and Blue (255, 255, 255 on the "digital scale").

White balance is set using a "neutral" color, so you could use pure white as above or any other "shade of gray" that is neutral such as a gray card (which would have equal "numbers" for R, G and B).


I think I understand now, it the color of the card that has to have the equal color values in RGB. If thats not correct someone please set me straight.
Thanks again to all.

[FlyingPhotog]

I think I understand now, it the color of the card that has to have the equal color values in RGB. If thats not correct someone please set me straight.
Thanks again to all.

Apologies for going too techno-geek on ya... ;)

You've got it right. You want equal values for Red, Green and Blue to get a truely neutral white balance.

You have to use a consistant target to get consisitant results so a commercially made Grey Card is a very good choice.

[PhotosGuy]

So long as your target is equal in R G B values, you can use it to white balance. It takes about 30 seconds, & you really don't need to buy a gray card. If you shoot white paper ON THE METER READING, it will photograph gray, just what the cam needs for Custom WB. Use that exposure for the WB set-up.
It's pretty good for adjusting exposure too, when there are bright highlights that aren't important in the frame.
What’s best for exposure, Gray cards, white paper, expensive attachments for the lens?
Gray Card…White Paper. What’s best? (http://photography-on-the.net/forum/showthread.php?t=58677)

[Balliolman]

Use a Whibal.

[Dean Humphrey]

Now here's another question, recently while shooting the State Softball Tournament at the stadium where its held in the evening, the shadows grow across the field. I used auto WB I had shot at times in shade and at times in full sun. Is it best to auto WB , custom WB obviously has to be done in sun or shade, just not sure what is correct.
Thanks Again

[tonylong]

I'd shoot in RAW, Auto WB, then adjust it to fit later. Often, Auto WB will handle such outdoor settings well. It has more problems with lights and indoor shooting.

[Dean Humphrey]

I'd shoot in RAW, Auto WB, then adjust it to fit later. Often, Auto WB will handle such outdoor settings well. It has more problems with lights and indoor shooting.

Sounds like a plan, thanks.

[PhotosGuy]

Waiting to adjust WB after shooting RAW may be a mistake. Curtis N found that a blown red channel is a problem:
How NOT to expose to the right (http://photography-on-the.net/forum/showthread.php?t=93712) Often, Auto WB will handle such outdoor settings well. It has more problems with lights and indoor shooting. AWB is very poor indoors & I don't use it for anything anymore. Notice that the very last exposure in the 2nd group of tests was of a gray card, & it's way off.
http://photography-on-the.net/forum/showthread.php?t=54281 ...recently while shooting the State Softball Tournament at the stadium where its held in the evening, the shadows grow across the field. I used auto WB I had shot at times in shade and at times in full sun. Is it best to auto WB , custom WB obviously has to be done in sun or shade, just not sure what is correct. Tough situation! I'd shoot RAW (always) & probably use the sun pre-set since the results would tend to be cooler with the shade shots & not blow the red channel.

I'm wondering where you got the idea that, "custom WB obviously has to be done in sun or shade?" You can use it anytime in any light. Don't expect excellent results with any WB in mercury or sodium lights, though. The full spectrum just isn't there.

[Dean Humphrey]

Waiting to adjust WB after shooting RAW may be a mistake. Curtis N found that a blown red channel is a problem:
How NOT to expose to the right (http://photography-on-the.net/forum/showthread.php?t=93712) AWB is very poor indoors & I don't use it for anything anymore. Notice that the very last exposure in the 2nd group of tests was of a gray card, & it's way off.
http://photography-on-the.net/forum/showthread.php?t=54281 Tough situation! I'd shoot RAW (always) & probably use the sun pre-set since the results would tend to be cooler with the shade shots & not blow the red channel.

I'm wondering where you got the idea that, "custom WB obviously has to be done in sun or shade?" You can use it anytime in any light. Don't expect excellent results with any WB in mercury or sodium lights, though. The full spectrum just isn't there.

I think I did not relay my thoughts exactly, what I meant to say is, if one does a custom WB in sun or shade, it could impact the to other area (sun or shade) I didn't mean to say you could only custom WB in sun or shade.
Thanks