iPhoto '06 makes it easy to adjust the duration of your slides, and it couldn't be simpler to make impressive shows with judicious use of the Ken Burns Effect. But even the most advanced presentations from iPhoto are just a jumping-off place for iMovie slideshows. Where iPhoto is image-centric, iMovie lets you take a broader stance, and look at elements and their durations in a different way.
Where iMovie Kicks In
The first thing you probably noticed when you clicked the Preview button in iPhoto was that the slides preview without any sound. While this allows you to focus on the image and its motion, it does not make for easy synchronization with the music track. iMovie always shows images and sound together. This is one reason why you might use iMovie instead of iPhoto for a dynamic slideshow.
The next thing you may have noticed when you selected any frame in your slideshow and clicked Play (instead of Preview) was that the selected music started at the beginning even though you may have wanted it to play from the middle of the slideshow. Unfortunately, there is simply no efficient way to link certain sounds to individual images in iPhoto. Adding music is ancillary to the slideshow process. Music is integral in iMovie, and it always maintains the proper relationship of images to sound and music.
Third, while you can control the duration of each slide in iPhoto, you are limited to whole-second increments: A given image might be onscreen for 1 second or 3 seconds, but never 2½. In many cases this would hardly seem to matter, but for precise synchronization of images to sound, a finer degree of control is important. iMovie works in units that are fractions of a second (1/30th of a second, to be precise).
Finally, there are no title or text capabilities in iPhoto, but there are in iMovie.
There is something in iPhoto called Show Titles in the slideshow Settings window. This is not to be confused with the flexible and customizable titles in iMovie. In iPhoto, this displays the image titlewhich might be something like DSCN0100, if you didn't change the name your camera assigned.
For Christopher's final version of his dynamic iPhoto slideshow, he didn't need any text onscreen, and he didn't really care where images transitioned from one to the next with regard to the music. But Jennifer does.
Making Movies Without a Camcorder
It would be natural to assume that, since iMovie is designed for making movies, you would need a camcorder to explore its power or to create interesting projects. This is not the case. Even with only a still camera (and iPhoto), you can use iMovie to build sophisticated and dynamic slideshows, which is another word for videos.
Jennifer used an iPhoto slideshow as a way to generate automatic in-store presentations of customers' pieces, but she also wants to use her photos to educate customers about interesting painting techniques. Some images need to be onscreen just as something is happening in the music; she might want to add narration at some point. She wants to add text to the screen, and she needs the text and titles integrated with the images and music. So she is going to make a slideshow in iMovie.