Hi,
Usually FCP defaults to a linear move, so the zoom should have been the same speed all the way through. Sometimes a zoom looks like it speeds up, but actually just the image ‘looking’ faster due to the fact the size is closer to the screen. (not a good explaination)
If you go to the motion tab, you can rt click (control click) the keyframe and choose ‘smooth’ This should fix it. But if it doesn’t then you have ‘key frame handles’ that will give you control of the speed in relationship to the keyframe.
Good Luck,
Todd at UCSB
Television Production