I've been doing manual WB for a few years and just had the strangest experience. I tried to do a WB in my office with the ExpoDisk, Light Grey & dark grey and white card. All four methods gave me the same result. A yellowish cast??? My D200 confirmed that I had a good Pre? So what gives? I also tried 3 different lens "2-f/2.8's and one f/1.4" and same result? In that room the best I got was using one of the presets. All without flash.
Any ideas anybody?