Bob,
I was just looking over the two images you posted. My take on the
matter is that
1) the original image is just a tad under exposed with the
excpetion of the red channel. In this instance using the cameras
meter, it tried balancing the tone of the image more toward grey.
That is, it looked at the scene and tried to do the best it could
in setting the exposure for the scene. The meter appears to be
fooled just a little bit by all the snow which is causing the
underexposure. This is causing the snow to look grey and dingy
where you know from looking at the original scene that the snow was
a nice bright clean white that may have had a blue or maybe a warm
tint.
If you were to try this again under the same circumstances, I would
add + 1/3 to + 1/2 compensation and your snow should come out
white. I own and use a D1X and D1H and when I work over snow, I
usually might need to add about +1/3 for the compensation. This
depends on if the snow is in bright sun or shade.
2) Cloudy -3 - a fair number of people use this setting becuase of
the suggestions of some well known individuals. I am not entirely
convinced this setting is ideal for most situations. Generally what
it is suppose to do is warm things up in the image. It is my
experince that more times then not, it will just give an odd
looking yellow/red/orange cast to the image. A lot of this really
depends on the color temperature of the light you are in.
This setting my explain why your red channel is on the verge of
over exposing. Since I was not there, and I can only get the gist
of how sunny or cloudy it was from what I see in the image, I would
have set the WB to just Cloudy or maybe set a manual white balance.
From your adjusted image, it seems you saw the snow as a pretty
nice powdery white. And your adjustments seemed to have taken the
color cast out of the image which was most likely produced by the
cloudy -3 setting.
I think the best way to warm an image up is to use a warming filter
instead of trying to warm things up with the cloudy -3 setting. I
have much better luck and get nicer images using the filter.
So next time, try adding a little + compensation and choose either
sunny or cloudy depending on the circumstances. The one thing above
all else, is to really get to know how your camera meters in all
cicumstances. Once you are at this level, you will automatically
know how to compensate for the shortcommings of the meter. No meter
is perfect or infallible and no meter can give you perfect
exposures in every circumstance.
Another thing you might try to do is start thinking about the sunny
f16 rule and also create your self a cloudy rule similar to the
sunny f16 rule. Knowing this rule and any derivatives will allow
you to know when your meter is not exposing a scene properly. You
might also want to get a low cost incident meter for setting
expsoure. This is how I work 90% of the time.
Ken
http://kenmcvayphoto.clymbers.com
