I understand the histogram is a weighted average of the RGB channels. However, do the blinkies blink when the same weighted average blows out or are they tied to the individual channels such that you get a blinkie if any one of the three channels blows out?
The blinkies in all of the cameras only blink if the RGB value is 255,255,255. They will not blink if you blow out an individual channel.
I know this because I hauled my camera down into a muddy poppy patch during the evening light and was not careful about checking histograms. Orange light + orange flowers = blown the heck out color channels... but no blinkies. Oops.
Very yellow as well as red flowers will blow out a channel or 2 while the histogram shows all is well. Similarly this can happen at dusk in the "blue" period.
On my D70, the blinkies came on below 255. If I recall it was about 240 or so when compared to the Adobe Raw Converter histogram...
I agree with Guy, 255 should be an "accurate" representation of the highlights.
I do not trust the blinkies in my D70S precisely for what has been already discussed. A color histogram, that we do not have in the D70S, would be a much better representation of the RGB channels.
