Alrighty Shrambo I made a quick tutorial on doing 15fps in FCP...here goes:
Step 1:

Make a new project in FCP (with a new sequence of course)
Step 2:

Drag in your images, organize them into bins, etc...get your content into FCP
Step 3:

Right click on your sequence and go to settings. Take note of the size and compressor of your photos.
Step 4:

In the sequence settings, set the frame rate to 29.97 (30) fps.
Step 5:

Set the sequence compressor to match what it said on your images.
Step 6:

Leave the sequence settings and double click on your sequence to bring it up in the timeline. Drag in your images.
Step 7:

Select all your images and right click on them. Scroll down to where it says "Duration".
Step 8:

In the duration menu, leave everything but the last value at zero. Make the last number 2.
Step 9:

Everything looks a bit smaller after hitting Ok. Play back your movie. It should run smoothly!
A note about step 5. If you that every little change you make in your sequence requires a render, go back into sequence settings and play around a bit until that no longer happens. My images were cropped to 1920x1080, you should make your sequence setting reflect the size of your images or you'll get letterboxing or stretching and other things we don't want.
Tell me if that helps!
Last edited by Realm of the Unreel (July 30, 2012 (09:00am))