Hendrik C. wrote in post #9861106
Just a quick question about the "select white balance by eyedropper tool"-thing:
Is there any tool to select more than ONE pixel for doing that in the RAW converter of your choice? I'm asking because if you have something like the 50D (I'm currently using one) and you have to deal with medium noise even at lower ISO settings, the chance that you will select a "noisy pixel" instead of a "clear grey pixel" is really high! It would be much better to select something like 30x30 pixel and take the average "white balance value" of them. Any solutions?
Everybody missed the boat on this one. The eyedropper does not select a single pixel whether it is DPP, ACR, or LR. A small area is averaged depending on the image size being viewed at the time. If I am not mistaken, in LR and ACR when viewing at less than 100% the area is 400 screen pixels (not image pixels). At 100% and above, it is 25 image pixels. (or maybe it is the other way around)
Don't worry too much about about being ultra precise since the color of light is not perfectly homogeneous anyway unless you are shooting in a very precisely controlled laboratory environment. When shooting nature and landscape images outdoors on a sunny day there are two strong sources that are quite different in color temperature -- the dominant lighting is direct sunlight which is basically from a point source and then there is the filtered blue sky light which is essentially omnidirectional so all light shadow areas will be illuminated by the open sky lighting. There is also an abundance of lighting that is reflecting off the various environmental features -- green from trees, blue from water, reds and all sorts of colors from rock features such as canyons. The end result is that different parts of the image are being illuminated by light from various sources and that is what gives them interest.
There is a definite downside to trying to white balance lighting in many situations such as nature and landscapes because it will kill the mood that you see before you snap the shutter. For example shooting a rainbow with a dark storm cloud in the background produces a beautiful light that sets the mood of the image. Converting the light to a condition where white is the same as white in daylight will completely kill the image and probably cause the rainbow to disappear. A similar situation exists if trying to WB a sunset. When I am shooting turned wood art objects in the studio, I work very hard to fine tune the WB, but when shooting outdoor scenery and nature images, I try to "romance" the lighting in PP to recreate what I saw in my mind's eye.
If using a gray card for WB make sure that it is not a cheap gray card because the cheap ones are often not neutral. They are intended primarily for exposure so sometimes they are not also satisfactory for WB. Ordinary plain laser copier paper is very good, but do not use ink jet paper because it often has UV optical brighteners which will really screw up WB. I have several different Xrite cards along with WhiBal cards which all work well and produce about the same results as ordinary copier paper.