"Sea Squid"
** The depth of field ( aka depth of focus) of a lens with a small aperture is very wide - even a moderate telephoto lens can, when set to F16 or higher, be in good focus from a couple of metres to infinity.
> But the camera has to stay in focus before it can shoot. In the movie, all
> the pictures in the few frames before blackout are all in focus.
>
Interestingly - the depth of field of a lens depends only on the size of the field of view and the F number. When the subject is very small ( ie like a postage stamp) then the depth diminishes to a millimetre or so.
........... Phil