Big troubles with camera

[Billy_the_Kid]

Hi all,

I have some troubles with a take and I would like a little help from you.

I have a 3D camera moving through the clouds (made in 3D, too) in the sky.
This camera will fall down in the direction of a boat, floating on the ocean (boat and ocean are 3D again).
The camera will getting closer of a real man stand on the 3D boat 'till we see his eyes.

This way:
How is the best way to do that? Maybe I use the 3D camera until the man appears, then change it for a real camera.
Is there a way to do this? How can I do?

Any help will be great,

regards,

Carlos Eduardo