Apple Final Cut Express HD - Manual (Page 510)

510 Part VII Fine-Tuning Your Edit
Having Handles at Edit Points
Clips must have handles if you want to transition between them. Handles are
additional media frames before the In point and after the Out point of your clips. The
first shot in a transition (the outgoing clip) needs a handle after its Out point, while the
second shot in a transition (the incoming clip) needs a handle before its In point.
If the In point of your incoming clip begins on the first frame of the clip’s media file, you
have no handle at the beginning (or head) of your clip. Likewise, if the Out point of your
outgoing clip ends on the last frame of the clip’s media file, you have no handle at the
end (or tail) of your clip. If the clips don’t have enough media for the transition,
Final Cut Express HD attempts to make the longest transition possible with the available
clip handles. In some cases, you may end up with transitions as short as one frame, which
may be difficult to see in the Timeline and are generally not intended or useful.
Aligning a Transition in the Timeline
You can place a transition so that it starts on, centers on, or ends on the edit point
between two clips in the Timeline. You should choose a transition alignment based on
the editorial effect you want to achieve:
 Starting on the cut: Choose this alignment if you want the last frame of the outgoing
clip to be fully visible before the transition begins.
Handle of incoming clip
Handle of outgoing clip Edit point
Incoming clip Outgoing clip
A transition starting
on the cut