Janis Whitcomb (Trotting Horse and second link) (Yahoo! FZ10 forum, 3 April 2004)...
If you are zoomed in and too close the camera will have a hard time {auto-}focusing. If it's too dark, the camera will have a hard time {auto-}focusing. The {auto-}focusing is usually what slows things down.See also section (shutter lag times).