The NokiaBlog has posted a video showing how the Nokia N900 handles video recording. You can focus and lock it for video, but it’s not possible to change the focus during recording.
About the Author: Jonne is a mobile phone enthusiast who is currently pursuing his Bachelor's degree in Computer Science at the Vaasa University of Applied Sciences. He has been using the newest phones out there ever since the Nokia 5110 was released. Currently his choice of smartphone OS is Windows Phone 7.5.