White balance under mixed fluorescent and daylight is very tricky … it's constantly changing as the fluorescents cycle 60 times a second, never mind how the daylight might be changing as well due to passing clouds, etc. The AWB setting is constantly trying to match what it sees and determine a neutral gray tone, and it's rarely successful in these circumstances with any camera.
Most Fluorescent lamps do not put out a continuous spectrum due to the way they produce light by fluorescing—exciting an exotic chemical substrate with electrical fields. The Daylight, Natural, Warm white, and Longlife color balance variations each have their different spectral signatures that the color temperature settings try to accommodate by approximation; they miss more often than they hit. I don't use any of those. If I'm going to be doing a lot of shooting in mixed daylight and fluorescent illumination, I lock the camera's white balance to some arbitrary color temperature and shoot a few sample frames of a Color Checker chart as the light shifts while I'm shooting my subjects. That way, at least the capture is happening at a consistent setting and the corrections will be more or less consistent from frame to frame. I can use the Color Checker sample shots to output a few different camera calibration profiles using the Xrite Passport software and try to accommodate the shifting that way too. It's a tough lighting situation. You just have to work around the challenge it presents. G On Apr 25, 2014, at 3:19 AM, Eric Weir <[email protected]> wrote: > > I don’t understand what it is. I don’t understand how it works. In some cases > I don’t know how to get the results I want. > > This is an album of images taken mostly in a classroom, the same classroom, > the same day, over a period of about an hour and a half. > <https://www.flickr.com/photos/eeweir/13974421313/in/set-72157644174507442/> > As you can see, the coloring differs widely across the images. I tried to get > them to come out the same without success. > > Since posting these I’ve gone back to the images in LR and changed the WB > setting to auto and increased the exposure on a couple slightly. That gives > me the best most consistent results. But “auto” leaves me completely in the > dark. What could *I* have done to achieve the same results? > > While I’m at it, could someone please explain to me what the options under > the fluorescent setting—D, N, W, L—are? I don’t see that it makes any > difference what setting I use. And I generally don’t like the results I get > with any fluorescent setting. > > Thanks, > ------------------------------------------------------------------------------------------ > Eric Weir -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
