They're not as popular anymore, but you still may own a camcorder that employs MiniDV tapes, DV, or HDV. These connect to a Mac through FireWire, but remember that fewer and fewer Mac models have FireWire connectors, so you may need an adapter.
Apple sells a Thunderbolt–to–FireWire adapter. And if you happen to have an Apple Thunderbolt display, it has a FireWire port. For the moment, though, let's assume that you have a Mac with FireWire and a FireWire–capable camcorder. Proceed with the following steps:
Connect one end of the FireWire cable to your camcorder and the other to an available FireWire port on the Mac.
Switch the camcorder to VTR (shorthand for video tape recorder) mode.
Camcorders vary; some devices call this Play or VCR mode.
Click the Import button on the toolbar or choose File→Import Media.
Choose your camcorder by clicking its name in the Camera section of the iMovie Sidebar.
The import viewer shows the image from the current position of the tape in the camera.
Use the mouse or trackpad to position the pointer in the upper portion of the import window.
If you want to advance from one clip to the next, or go back to look a clip that comes before the one you're viewing, click the Next button or the Previous button, respectively.
If you happen to be more than 5 seconds deep into a clip, clicking the Previous button takes you to the start of the clip that you're currently in. To fast-forward or rewind rather than jump from one clip to another, position the pointer over the Next button or Previous button, and hold down the mouse or trackpad button.
Do one of the following and then click OK:
If you want to choose an existing event to import clips into, choose the event from the Import To pop-up menu at the top of the import event.
If you'd rather place the footage in a newly created event, choose New Event from the Import To menu and name the event.
When you're at the point in the tape where you want your movie to begin importing, click Import.
iMovie imports from where you are to the end of the tape unless you click Stop Import or Close instead.
When you're done importing, click Close to close the Import window.