When you consider the amount of work required to make your own movie trailer from scratch, the new Movie Trailers feature in iMovie ’11 will amaze you. In just a few minutes, you can create a short film with production values that rival what you see on the big screen.

But is that all there is to iMovie’s trailers? Did Apple put in what was plainly a lot of work – many of the soundtracks were recorded by the London Symphony Orchestra, for heaven’s sake – simply to build a fun little feature?

Fortunately, the answer is no. Movie Trailers offers a lot more power than is apparent at first glance. You can fine-tune edits, customise cast members and even use the trailer as a starting point for a larger project.

The following sequence assumes that you already know the basics of creating a movie trailer. If not, consult iMovie Help first. To start with step 1, you need to have already created a project and chosen a trailer template.

Double-clicking a clip in the Storyboard interface lets you apply video or audio effects to your trailer

1. Fine-tune edits

When you’re choosing footage for a scene, don’t worry about highlighting the precise 1.3 seconds you want; just select a rough range of frames within the clip you want to use. Here’s how to change the frames that are included:

First, in the Storyboard tab of the Project browser, point to the clip you want to edit. Then, click the blue button that appears at the lower left of the clip when you hover the mouse over it. The Clip Trimmer drops into view over the Event Library and the Event browser. (Two other buttons are also visible: one mutes or unmutes the clip’s audio; the other removes the footage and displays the placeholder animatic.)

Next, drag the active area to a new position within the overall clip. The scene’s duration time doesn’t change, so all you can do is slide the highlighted area within the clip. (Tip: To quickly preview the footage, press the forward-slash [/] key.) Click Done to make the change.

2. Apply clip adjustments

Double-click a clip in the Storyboard interface to call up iMovie’s familiar Inspector, which facilitates clip adjustments, such as applying video or audio effects and enabling image stabilisation. For example, you could set all clips to be black and white in a Film Noir-style trailer.

Similarly, select a clip in the Storyboard and click the Crop button in the toolbar to crop, rotate or apply the Ken Burns effect to it.

3. Move or duplicate clips

Would a clip you’ve already placed work better in another spot in the Storyboard? Just click and drag the clip to another location – if it already has a clip, the new one replaces it. If you hold the Option key as you drag, iMovie creates a duplicate – helpful if you want to use a separate section of the same scene.

4. Change cast members

Every movie-trailer type includes cast members, but a few let you add or subtract characters and iMovie now offers multiple soundtracks to accommodate different numbers of cast members. In the Blockbuster, Friendship and Travel trailers, go to the Cast list in the Outline view and click the add (+) or subtract (-) button to the right of a cast member’s name. You can have as few as two and as many as six identified characters.

In the Pets trailer, use the Pet Type field to specify Dog, Cat, Horse or even Monster. The animal tracks that appear in the text screens reflect your choice.

5. Convert trailer to project

A studio movie trailer offers a taste of what’s to come, and an iMovie trailer can function the same way. To use the trailer as a jumping-off point for editing the full version of your movie, choose File > Convert To Project. (We recommend duplicating the trailer project first – choose File > Duplicate Project in the Project Library.)

The trailer becomes a standard iMovie project, with all edits appearing in the Project browser – as if you had already spent a lot of time building it manually.