Need to dive into a CG mouth

[Stokes McIntyre]

Hi Everyone,

 

I am putting together a shot that involves diving into the mouth of our subject. We are starting on a live action cowboy shot of the character lying in bed. The camera will slowly drift down towards the character. The character is going to gasp and then suck the camera towards his mouth. The inside of the character's mouth will be CG and therefore we will transition from a practical camera to a CG camera as we move into the character's mouth and down his esophagus. Ideally, I would like to maintain focus as we move towards the mouth of the character and we need to get close to the mouth before we can effectively transition to CG. We are shooting on the HPX500 DVCPRO HD camera with digiprime lenses. Any recommendations on how to maintain focus throughout this move? Will we need some diopters? I imagine shooting on the wider side of the lens set for a more dramatic move. Close focus on the 20mm digiprime is 20". My concerns are close focus, maintaining focus throughout the shot, a steady move, and how to stop the move abruptly yet smoothly at the end of the move (so we don't hit the talent). Any suggestions for techniques or equipment that would maximize the success of this shot?

 

 

Thanks!