I want to sync videos from my iPhone to my computer, but I can't seem to do this? Please help?

I have a Mac OS. When I plug my iPhone 4s nto my computer, it will show up under the iTunes finder, but it won't show up on the finder for my computer. There isn't an option in iTunes to sync my iPhone videos from my camera roll into my computer....so I figure the way to do it must be in the finder? Can anyone please help me do this? I'm not used to working my iPhone, it's pretty new. Thanks!