D800 - Blue sky turns white

It's easy to overexpose sky, especially while trying to maintain foreground subjects that are nearly backlit.

Technically, you can try a global EV-1/3 or EV-2/3 exposure and add in ADL of the High or Extra High persuasion. ADL's biggest effect is to reach into the highlights for more tonality.

RAW shots will often show sky tonalities that their accompanying JPEGs don't keep.

-iNova