Posted by Patrick Nixon on April 24, 2008 at 10:16 PM
While shooting today in open woods under bright blue sky with high overcast, white balance under Auto and P modes came out consistently blue. Switching to Manual and cloudy white balance solved the color problem.
It is always better to try to select the most appropriate WB manually. If conditions change fast auto is acceptable. However, if you shoot in RAW you will always be able to modify it to suit the image during RAW conversion. You might want to avoid using P mode. It offers little option for exposure compensation for the specific conditions in which you are shooting. Give Av and Tv a try. Most of us use Av and manual, again depending on conditions. In stable light manual helps a lot. If the light is changing Av works well.
Posted by Patrick Nixon on April 25, 2008 at 12:46 AM
Yep, sure enough the problem is the inability of the camera to measure the color temperature of the ambient light properly. The images I shot were in RAW, so I was able to correct by increasing to 6000K in Camera Raw. (Would have had to adjust "by eyeball" in Photoshop CS2)
The Nikon D70s I'm using allows adjustment of WB to cloudy (6000 K) or shade (8000 K) or to a preset value measured from a gray card or a properly exposed image on the memory card.. But I can't help but wonder whether the camera will measure correctly even from a gray card if it cannot measure ambient color temperature from another scene correctly. Apparently the D70s cannot be set to a specific numeric color temperature.
Posted by Zack Schnepf on April 25, 2008 at 2:41 PM
In all honesty, I never worry about WB. If you shoot raw, there really is no need, you can just choose your WB during processing. I'm probably in the minority though, color accuracy isn't really important to me. If I were a documentary photographer, or a commercial photographer then I would be more concerned with color accuracy, but I'm more concerned with recreating the emotional impression I had when I was there.
Posted by David Bostedo on April 25, 2008 at 3:18 PM
But I can't help but wonder whether the camera will measure correctly even from a gray card if it cannot measure ambient color temperature from another scene correctly.
Patrick - I'd guess that it would measure the gray card correctly. Figuring out the white balance from an actual scene with various tones and lighting is infinitely more difficult than from a more evenly lit gray card. Of course, if you have a standard gray card, you could pretty easily test it by shooting it say, indoors under tungsten light, and outside in the sun.
I think your camera may have the option to shoot something that's white as well as grey, which can be easier to find sometimes. Bright white paper, for instance.
Posted by Patrick Nixon on April 25, 2008 at 3:46 PM
I repeated the exercise today at same scene with nearly the same light conditions. Iset the whibte balance using a standard gray card. But the camera only corrected about 1/2 as much as needed. So, the WB measurement is not perfect. All the more reason to shoot in RAW and post-process in Camera Raw, where a specific color temperature can be chosen.
Camera RAW is easier because all colors are changed appropriately by changing color temperature. If shot in JPEG and post-processed with Photoshop CS2, the cyan/red, magenta/green, and yerllow/blue channels must be altered independently.
If shot in JPEG and post-processed with Photoshop CS2, the cyan/red, magenta/green, and yerllow/blue channels must be altered independently.
Not necessarily.
Using the grey eyedropper in the Levels or Curves dialog and clicking on a grey or neutral tone is usually enough to correct the problem.
It's a damaging step though, and a moot point if you shoot in RAW.
Discussion
7 repliesWas this my error or the camera's?
Pat Nixon
The Nikon D70s I'm using allows adjustment of WB to cloudy (6000 K) or shade (8000 K) or to a preset value measured from a gray card or a properly exposed image on the memory card.. But I can't help but wonder whether the camera will measure correctly even from a gray card if it cannot measure ambient color temperature from another scene correctly. Apparently the D70s cannot be set to a specific numeric color temperature.
Patrick - I'd guess that it would measure the gray card correctly. Figuring out the white balance from an actual scene with various tones and lighting is infinitely more difficult than from a more evenly lit gray card. Of course, if you have a standard gray card, you could pretty easily test it by shooting it say, indoors under tungsten light, and outside in the sun.
I think your camera may have the option to shoot something that's white as well as grey, which can be easier to find sometimes. Bright white paper, for instance.
Camera RAW is easier because all colors are changed appropriately by changing color temperature. If shot in JPEG and post-processed with Photoshop CS2, the cyan/red, magenta/green, and yerllow/blue channels must be altered independently.
Not necessarily.
Using the grey eyedropper in the Levels or Curves dialog and clicking on a grey or neutral tone is usually enough to correct the problem.
It's a damaging step though, and a moot point if you shoot in RAW.