This is discussion archived from a time before the current discussion method was installed.
Ununnilium: It's a subtrope. It should be linked to on there, but it can stand as its own entry.
Triterope: They're definitely related, but I think Close-Up on Head should be a separate subtrope. The Reveal Shot reveals an entire scene, or something so big that it changes the direction of the entire scene. And, usually, the characters are seeing it for the first time as well. Close-Up on Head is more for quick-hitter comedy gags. The other characters can see what's going on, and are past finding it amusing, but the gag is in keeping it secret from the viewer for a moment.
Grev: Can we get a screencap of the extreme close-up of Daffy in Duck Amuck for a page pic?