I was shooting red tomatoes and peppers today, just for fun. Daylight, Minolta colormeter suggests 5800K. First attempt: auto everything. Reds are blown out beyond recovery. Second attempt: auto WB, exposure compensation to get the red channel histogram just touching the right wall. Image underexposed, "correcting" exposure in post-processing brings way too much noise - it needed +1.3eV. Third and forth attempts: custom white balance with auto exposure and manual exposure compensation - same as above, red blown out or strong underexposure. Fifth attempt: - took custom white balance, - then shoot colour chart with it, - then shoot tomatoes, increasing exposure (against suggested by camera meter 1/20 all the way to 1/8!!!) and white balance on the camera so that blue channel just started to touch right wall on the histogram - I was to adjust colour temperature setting on the camera to 3800K, - opened colour chart shot, used click-white balance (minor change from preset), stored the values of white balance, - opened the tomatoes shot @ 3800K, applied the saved white balance - nothing is blown out, good colour and details in color channels, - took some shots using Auto WB, settings around daylight (direct sunlight, cloudy, +/- compensations), and manually setting 5600, applied white balance from colour chart shot - and was able to get the reds not blown out only by underexposing the image.