Focus is an incredibly effective tool for directing the audience's attention.
Most of us don't think twice about the shutter speed that our video camera is using. True: it can be set to manual, but since the camera can automatically take care of it, why should we bother?
Looking at a well-balanced image, we see that it has a settled, stable look. An unbalanced shot, on the other hand, has an insecure, uncertain feel to it.
With some of the new inexpensive digital video effects technologies available today, it's possible for a home videographer to create visual sequences that were unthinkable in most Hollywood post-production studios just a generation ago.
There is probably no more reviled filming technique than the "shaky cam", or the vomit cam as it is derisively referred to by those that it sends running from the movie theaters with hands pressed over mouth.