This previous hint shows how to turn the Ken Burns Effect on and off for the entire slide show.
You can also set a custom Ken Burns Effect starting and ending point for any photo in your slideshow. Used with the Automatic setting for most slides, custom starting and ending points on specific slides allows you to highlight special features of the photo.
In your slideshow, select the photo you want to adjust and check the box "Ken Burns Effect". Click on "Start." (highlighted in red in the first illustration) Use the zoom slider (also highlighted in red) to zoom in and out of your picture and drag the picture around until you have found the perfect starting point for the effect.
Next, click on "End." Zoom and Drag to your desired ending point. In the second illustration, you see the ending point. The green highlight shows the original starting point.
When your slide show runs, instead of the automatic Ken Burns effect, the slide will zoom and pan from your starting point to your ending point.
Related Items: iPhoto | Ken Burns | slideshow