This tip uses the new multicam clip feature of Final Cut Pro X that was introduced in the 10.0.3 update.
Multicam clips are designed to synchronize multiple camera angles of the same physical actions. You can then use these clips in projects - switching between angles in the same clip on the timeline.
One of the interesting features of multicam clips is that you can edit the angles - changing the sync between clips, add angles, edit audio tracks and add effects to individual angles. Once you make these changes, the modifications are available to each instance of the multicam clip on the timeline.
This is a useful feature for single clips too. This video shows a clip being made into a multicam clip (by 'synchronising' it with a still image). Multicam clips usually use audio or timecode to sync angles. As there is no audio or timecode built into stills, the new multicam clip is made with the clip and the still in separate angles. As the still's name starts with z, the clip is added to angle 1, the still to angle 2. The multicam clip therefore defaults to showing angle 1, the clip we want to work with.
After you add sections of the multicam clip to multiple times in a timeline, you can add or modify effects (or make audio changes) to the clip inside the multicam clip by opening it in the angle editor and making changes to the clip. When you return to the timeline, every instance of the multicam clip will have changed.
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